# I don't think amp SQ has changed much over the years



## slipchuck

I think, in my own opinion, that amps are only made to "amplify" the signal from the HU as is... no more, no less. it should not change the SQ at all because that is not the true job of the amp, it is that of the source signal. no coloration, boost or extension of frequencies unless it is by the owner's tuning
I think over the years amps got smaller, more powerful, cheaper, less power hungry.but SQ is much the same.
good quality is much more obtainable now then 20 years back.(my first cd unit was worth more then some systems combined today)
some of the home stereos that sound the best are based on tube technology from decades back! and cost thousands like the carver silver 7 mono amp.
I think there is not to much difference in old school vs new school except the above opinions.

this is for debate, not who is right or who is wrong
anyone agree or disagree?

thanks everyone


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## ChrisB

Let's further add to this discussion by stating how and why the difference between quality amplifiers makes a difference in the most hostile environment for audio reproduction, i.e. the car itself! 

Note: it's a trap, with the emphasis on quality.


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## trumpet

ChrisB said:


> Let's further add to this discussion by stating how and why the difference between quality amplifiers makes a difference in the most hostile environment for audio reproduction, i.e. the car itself!
> 
> Note: it's a trap, with the emphasis on quality.


I've come to learn after reading the latest NwAvGuy blog post that people want to live the fantasy of "spending more money on equipment always leads to better sound reproduction". It won't stop me trying to guide people to start using their brains again, but I know now to not force an unneeded argument lest I waste more of my time.


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## ChrisB

trumpet said:


> I've come to learn after reading the latest NwAvGuy blog post that people want to live the fantasy of "spending more money on equipment always leads to better sound reproduction". It won't stop me trying to guide people to start using their brains again, but I know now to not force an unneeded argument lest I waste more of my time.


It is amazing what people will believe because they want to believe. I used to fall into that category myself, until I noticed that I couldn't tell the difference between old school, new school, and full-range class D in a moving car. So either I'm tone deaf or others believe in SQ fairies and SQ unicorns.

Regardless, I am happy that I came to my senses and chose to approach my car audio projects from a more scientific perspective. Since then, I managed to save a lot of money, headache, and grief. I just feel sorry for those who haven't come around and still believe in tuning their system via amplifier swapping. Poor people, they are destined to be forever parted from their hard earned money.


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## Dr.Telepathy SQ

It's easy to manipulate the uneducated. Draw upon their emotions and their pockets. Same tricks applied in our political system and purchasing options as consumers. 

Rarely do people listen to objective data or search for the truth. 

I would contend that the most drawing options to amps, in my book, are size, current draw, and output. I tend to like efficient set ups, so class D power is nice to have. But, I'm not paying high prices for the taking. True, some amps do a better job of shielding noise, crossover selection, etc..

I've benched many amps, looked at data, sold and purchased many amps, truthfully, as long as it's from a reliable company, I don't see much difference in amps. After $500, the performace v. dollar question should come into play.


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## [email protected]

A ****ty pre-amp definitely affects the sound. But do we seriously need to get into this subject for the bazillionth time.


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## tai01

ChrisB said:


> It is amazing what people will believe because they want to believe. I used to fall into that category myself, until I noticed that I couldn't tell the difference between old school, new school, and full-range class D in a moving car. So either I'm tone deaf or others believe in SQ fairies and SQ unicorns.
> 
> Regardless, I am happy that I came to my senses and chose to approach my car audio projects from a more scientific perspective. Since then, I managed to save a lot of money, headache, and grief. I just feel sorry for those who haven't come around and still believe in tuning their system via amplifier swapping. Poor people, they are destined to be forever parted from their hard earned money.


I have been following your posts and hope to learn more from you. As this thread primarily focuses on amplifiers and the unproved need to spend more to have better sound, what do you suggest instead of the brand name 5-channel Class-D amps like the JL HD900? 

I've been looking for equipment and browsing the forums, but don't like to create new threads if there is already a topic.

Thanks,
tai


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## Niebur3

BeatsDownLow said:


> A ****ty pre-amp definitely affects the sound. But do we seriously need to get into this subject for the bazillionth time.


Thanks! I had a long reply typed but I am hesitant to post it. ^^This is the correct response and as long as it is left to that, I'll keep my response to myself. 

I will just say, even if you don't see the sonic value (which I could argue to some degree) with high end amps, please don't knock someone else for merely owning one. After all, there are many reason people buy high end amps, just like people buy Acura, BMW, Lexus, Ferrari, etc. when there are many less expensive cars that can/do perform the same.


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## ChrisB

tai01 said:


> I have been following your posts and hope to learn more from you. As this thread primarily focuses on amplifiers and the unproved need to spend more to have better sound, what do you suggest instead of the brand name 5-channel Class-D amps like the JL HD900?
> 
> I've been looking for equipment and browsing the forums, but don't like to create new threads if there is already a topic.
> 
> Thanks,
> tai


You're not going to like my answer because I am seriously thinking of using a pair of HD 900/5s in my next setup.:laugh: If you must, I'd suggest looking into the following: Kenwood Excelon, 2012 Alpine PDX, Kicker, JBL, and Infinity for alternatives to the JL Audio HD series. Eventually the PPI amplifiers may get there, but I am hesitant to try them at this point in time. 

Then again, I already know that the JL Audio HD series will my needs and expectations, so why bother changing to something else? The only caveat is if I can make my current amplifiers work. I think they are too tall, but, we'll just have to wait and see.


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## slipchuck

tai01 said:


> I have been following your posts and hope to learn more from you. As this thread primarily focuses on amplifiers and the unproved need to spend more to have better sound, what do you suggest instead of the brand name 5-channel Class-D amps like the JL HD900?
> 
> I've been looking for equipment and browsing the forums, but don't like to create new threads if there is already a topic.
> 
> Thanks,
> tai


Don't get caught up in the "wattage wars" I only have 2 amps that are 50 watts RMS per channel and and it can deliver high SQ until you need to almost yell to the person with you.I run a lower cost sub and it improved SQ and brought it in to a new level of dynamics and it runs around 80 watts. Quality RMS is what to look for, not 1000 watts of garbage. Good quality name amp that can handle high dynamic range without distortion is what to look for.
There is a saying in photography... Garbage in = garage out. No amp can fix a bad signal from the HU.

Thanks so far everyone for your opinion and please feel free to post more


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## rain27

Niebur3 said:


> Thanks! I had a long reply typed but I am hesitant to post it. ^^This is the correct response and as long as it is left to that, I'll keep my response to myself.
> 
> I will just say, even if you don't see the sonic value (which I could argue to some degree) with high end amps, please don't knock someone else for merely owning one. After all, there are many reason people buy high end amps, just like people buy Acura, BMW, Lexus, Ferrari, etc. when there are many less expensive cars that can/do perform the same.


I vote for an amplifier shootout! 

Can't we just end this argument once and for all with a properly administered blind listening test?

Although these tests have already been done elsewhere and they've all been one-sided...


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## MarkZ

slipchuck said:


> Don't get caught up in the "wattage wars" I only have 2 amps that are 50 watts RMS per channel and and it can deliver high SQ until you need to almost yell to the person with you.I run a lower cost sub and it improved SQ and brought it in to a new level of dynamics and it runs around 80 watts. Quality RMS is what to look for, not 1000 watts of garbage. Good quality name amp that can handle high dynamic range without distortion is what to look for.
> There is a saying in photography... Garbage in = garage out. No amp can fix a bad signal from the HU.
> 
> Thanks so far everyone for your opinion and please feel free to post more


Where are all these head units that are supplying a bad signal? I don't get it.


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## sqshoestring

Amp swap certainly can change the sound, many times I swapped an amp and then I am messing with the EQ to get something right. I'd certainly say the more you spend the less change it will be. I've had some amps work better in a system, while not the most ideal in another system. That said they don't make much difference until you get to cheap no-name amps that are really bad. You also have to note the difference in power apart from the SQ changes. I don't swap amps for SQ reasons until I've used and tuned the system for some time, then I can note a difference or not. Overall many newer amps are very good SQ and cheap, compared to old school where you needed an above average amp to get some nice SQ...but not always. Speakers and install make way more difference. You need a good enough signal to supply the rest of the system, for example some tuners are far worse than others. All in my experience, though I have repaired some amps I don't have equipment to test SQ other than my ears. In my car I know what it sounds like and can tell if it has changed, and usually pick what works better meaning it EQs easier and is not fatiguing. High side amps that distort, I can't listen to them loud for long at all.


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## [email protected]

......


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## Z-Roc

to me it's the HU for sure


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## ChrisB

sqshoestring said:


> High side amps that distort, I can't listen to them loud for long at all.


You hit the nail on the head with this comment. The first time I experienced an amplifier that colored the sound, I was wowed and amazed by it. Then after getting some extended seat time listening to my favorite tracks from yesteryear, i.e. Pink Floyd, I started saying to myself "That doesn't sound right... Neither does that... WTF?" Nobody messes with my Pink Floyd!:laugh:


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## Niebur3

rain27 said:


> I vote for an amplifier shootout!
> 
> Can't we just end this argument once and for all with a properly administered blind listening test?
> 
> Although these tests have already been done elsewhere and they've all been one-sided...


Jeeez, let me get the mid-woofer test done first...lol! Remember, the one sided tests are stating that "If all amps measure the same, they will sound the same". What happens if I only level match the output voltage? What happens if I drive them just into clipping? What about headroom or lack thereof? What if we stress them some (like in the real world) instead of a test tailor made to do the opposite and prove a point that is very rarely indicative of the real world? 

Hmmmm.....I see a future test on the horizon!


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## ChrisB

Niebur3 said:


> Jeeez, let me get the mid-woofer test done first...lol! Remember, the one sided tests are stating that "If all amps measure the same, they will sound the same". What happens if I only level match the output voltage? What happens if I drive them just into clipping? What about headroom or lack thereof? What if we stress them some (like in the real world) instead of a test tailor made to do the opposite and prove a point that is very rarely indicative of the real world?
> 
> Hmmmm.....I see a future test on the horizon!


Going further, what if you install those amplifiers in an older car with lots of road noise and do the blind test at 70 MPH on the interstate?:laugh: Start looking for a CRX, a 90s Civic Hatch, or an Integra Type R to perform the testing in. Also, no MLV on the floorboard or firewall is allowed, but I will allow you to seal up the doors and deaden them.


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## MarkZ

Niebur3 said:


> Jeeez, let me get the mid-woofer test done first...lol! Remember, the one sided tests are stating that "If all amps measure the same, they will sound the same". What happens if I only level match the output voltage? What happens if I drive them just into clipping? What about headroom or lack thereof? What if we stress them some (like in the real world) instead of a test tailor made to do the opposite and prove a point that is very rarely indicative of the real world?


All valid concerns, but let me counter with a different question: what if you _don't _stress it and _don't_ clip it? In that case, would the cheap one sound (and measure) the same as the expensive one?

If it did, it would blow the mind of a lot of people.

So I think the controlled testing/unstressed scenario still tells us something useful. At the very least, it guides some decision-making... do you put extra money into buying an expensive designer amp? Or do you put extra money into buying a cheaper amp that's large enough not to be stressed or clipped?


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## slipchuck

MarkZ said:


> Where are all these head units that are supplying a bad signal? I don't get it.


Maybe a better way to express it would be poor dynamic range and distortion instead of bad signal. Kind of like comparing a unknown Chinese brand to Kenwood or something similar.

Hope this helps


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## MarkZ

Yeah, I know what you mean. I just haven't encountered that sort of thing before. Even cheap 15 year old head units do just fine. Most factory head units manufactured within the last 10 years do too.

The point being that it's cheap and easy to build a low-distortion high-dynamic range source. So if there are companies ****ing this up, what are they doing wrong? And are they doing it intentionally, for one reason or another?


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## slipchuck

ChrisB said:


> You hit the nail on the head with this comment. The first time I experienced an amplifier that colored the sound, I was wowed and amazed by it. Then after getting some extended seat time listening to my favorite tracks from yesteryear, i.e. Pink Floyd, I started saying to myself "That doesn't sound right... Neither does that... WTF?" Nobody messes with my Pink Floyd!:laugh:


When I was younger I thought the louder the better. Ears hurting and not hearing the buddy beside you. Then I grew up and bought some high end equipment.... Turned up the volume and my ears were normal. Then started to say something and had to speak as loud as with the first system. It only sounded 1/2 as loud until I opened my mouth. from that day on I knew what audiophile magazines wrote about
And my ears thanked me too!


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## rain27

Niebur3 said:


> Jeeez, let me get the mid-woofer test done first...lol! Remember, the one sided tests are stating that "If all amps measure the same, they will sound the same". What happens if I only level match the output voltage? What happens if I drive them just into clipping? What about headroom or lack thereof? What if we stress them some (like in the real world) instead of a test tailor made to do the opposite and prove a point that is very rarely indicative of the real world?
> 
> Hmmmm.....I see a future test on the horizon!


Well, the real world would include listening to car audio amps while actually driving the car...not that I think it would make a difference either way.

How would you compare "headroom" on amps of similar power? Even if the "sq" amp had more headroom than your average amp of similar power, wouldn't it be easy to just double up on power with another cheap amp? Watts are cheap these days.

And if this thread isn't convincing enough about the topic, I don't know what will be:

http://www.diymobileaudio.com/forum...level-matched-amps-head-units-sound-same.html

Except, maybe, an amp shootout!


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## ChrisB

rain27 said:


> Well, the real world would include listening to car audio amps while actually driving the car...not that I think it would make a difference either way.


It would if they were in the Integra Type R as I stated. The chances of one hearing ANYTHING over the road noise at normal volume is slim, much less determining which ess que amplifier gives the best eargasm.:laugh:


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## rain27

ChrisB said:


> It would if they were in the Integra Type R as I stated. The chances of one hearing ANYTHING over the road noise at normal volume is slim, much less determining which ess que amplifier gives the best eargasm.:laugh:


I agree. I meant that I don't think the sq amp could be determined whether in a quiet room or noisy car.

All of the tests so far have been in ideal listening environments and still no one in the history of amps has been able to distinguish one from another.

Not sure what other compelling evidence people need. But an amp test with car audio amps would strengthen what's already been established. 

Whoever administers the test will be referred to for years when people remember the test where no one could distinguish the Tru amp from the Kenwood.


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## Gary S

Amp distortion is a curve, not a constant. As long as you don't turn an amp up loud enough to hear noticeable distortion, you won't hear it. If you have to turn it up so loud that you hear distortion, it's either broken or you need more power.

Even high end midrange drivers, including some of the best I have ever heard - the distortion is around 3% - this is much higher than an unclipped amp. The speakers will mask any minuscule distortion from an unclipped amp.

If you are interested in sound quality, forget about distortion from head units and amps, it's not an issue. Instead, focus on the things that really matter, such as speaker quality, speaker placement, install and system tuning/design. And when you get all that right, take it to the next level and try surround sound.


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## Ampman

I agree with Gary S somewhat, however I'm an old school fan ive tried both new and old and I can tell a noticeable difference in the new verses old, the old in my opinion has a better response and are more linear with less distortion while I don't use special test gear to prove my point my ears tell me all I need to know. Just my opinion an my opinions don't count y'all have a good one.


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## oilman

I must have super human hearing. I can hear thin sonic free music at 70 mph.


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## slipchuck

I don't know how to measure headroom on an amp besides playing a passage of music like Our Lady Peace "is anyone home? " if the change in dynamic change of the music doesn't scare the crap out of you after the words "save me from this space" then something isn't right. You would then have to swap out for another amp and compare the two . Lots of work 
Maybe with an SPL meter?


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## tai01

ChrisB said:


> You're not going to like my answer because I am seriously thinking of using a pair of HD 900/5s in my next setup.:laugh: If you must, I'd suggest looking into the following: Kenwood Excelon, 2012 Alpine PDX, Kicker, JBL, and Infinity for alternatives to the JL Audio HD series. Eventually the PPI amplifiers may get there, but I am hesitant to try them at this point in time.
> 
> Then again, I already know that the JL Audio HD series will my needs and expectations, so why bother changing to something else? The only caveat is if I can make my current amplifiers work. I think they are too tall, but, we'll just have to wait and see.


I was on the fence with the HD900 because of the high price, but if it's going to satisfy my one amp does all requirement, then I will pull the trigger. Many of my "audio" guys have also stood by the JL HD while some go by the JL XD amps. If all goes well, I might be able to score a deal on the HD amp.



slipchuck said:


> Don't get caught up in the "wattage wars" I only have 2 amps that are 50 watts RMS per channel and and it can deliver high SQ until you need to almost yell to the person with you.I run a lower cost sub and it improved SQ and brought it in to a new level of dynamics and it runs around 80 watts. Quality RMS is what to look for, not 1000 watts of garbage. Good quality name amp that can handle high dynamic range without distortion is what to look for.
> There is a saying in photography... Garbage in = garage out. No amp can fix a bad signal from the HU.
> 
> Thanks so far everyone for your opinion and please feel free to post more


How do you distinguish quality RMS? I ran across this thread here with the eDHQS, that has been discontinued, a very inexpensive driver but does wonders in an IB setting. If a sub like that can be powered equally well with a decent amp and produce sound equivalent to a JL 10w3 powered by a 5 channel PDX...how do we tweak or change other components of the system?


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## slipchuck

tai01 said:


> I was on the fence with the HD900 because of the high price, but if it's going to satisfy my one amp does all requirement, then I will pull the trigger. Many of my "audio" guys have also stood by the JL HD while some go by the JL XD amps. If all goes well, I might be able to score a deal on the HD amp.
> 
> 
> 
> How do you distinguish quality RMS? I ran across this thread here with the eDHQS, that has been discontinued, a very inexpensive driver but does wonders in an IB setting. If a sub like that can be powered equally well with a decent amp and produce sound equivalent to a JL 10w3 powered by a 5 channel PDX...how do we tweak or change other components of the system?


I don't know how to answer the second part of the question, but what I meant by quality RMS is the ability of less power to sound as good or better then amps that clam to be much more powerful. Old school days a 50 watts of RMS per channel Blaupunkt would sound better than 500 watts from a cheap amp (for example early Pyramid amps)


Hopefully this clears up what I am trying to say


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## Ampman

oilman said:


> I must have super human hearing. I can hear thin sonic free music at 70 mph.


Humm most hear sirens at that speed


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## jgustin

Dr.Telepathy SQ said:


> I've benched many amps, looked at data, sold and purchased many amps, truthfully, as long as it's from a reliable company, I don't see much difference in amps. After $500, the performace v. dollar question should come into play.


What do you recommend in the $200 dollar range? I don't care if it's new/old/used, etc. I've used two JL Audio Slash v1 amps in the past and was pleased with those.

I recently started using an Eclipse XA4000. I did my homework, and thought I was getting a good quality class d amp with plenty of power, but I am getting that harsh, hurt my ears sound when I turn it up. I've tried it with Eclipse 3-way components, Infinity Kappa components, Massive Audio CKX components and Pioneer TS-D1720 components, two different Eclipse head units and now the new Pioneer head unit. They all sound good up to about 90db. After that it gets harsh.

It is rated at 125x4rms. I keep the gain set low to match the voltage from the HU and I never turn the HU past 80%. I tried bridging it, 350x2rms, to see if the extra power would help it not work as hard, and still had the same problem. I don't use bass boost or filters on the amp.

btw, I'm not looking to win an SPL competition, I just want to be able to comfortably get it to 100-110 db if I'm in the mood to crank it up.

Any thoughts or advice is welcomed.


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## slipchuck

jgustin said:


> What do you recommend in the $200 dollar range? I don't care if it's new/old/used, etc. I've used two JL Audio Slash v1 amps in the past and was pleased with those.
> 
> I recently started using an Eclipse XA4000. I did my homework, and thought I was getting a good quality class d amp with plenty of power, but I am getting that harsh, hurt my ears sound when I turn it up. I've tried it with Eclipse 3-way components, Infinity Kappa components, Massive Audio CKX components and Pioneer TS-D1720 components, two different Eclipse head units and now the new Pioneer head unit. They all sound good up to about 90db. After that it gets harsh.
> 
> It is rated at 125x4rms. I keep the gain set low to match the voltage from the HU and I never turn the HU past 80%. I tried bridging it, 350x2rms, to see if the extra power would help it not work as hard, and still had the same problem. I don't use bass boost or filters on the amp.
> 
> btw, I'm not looking to win an SPL competition, I just want to be able to comfortably get it to 100-110 db if I'm in the mood to crank it up.
> 
> Any thoughts or advice is welcomed.


I would try the advice I got from Crutchfield..
Pick a CD of good quality and dynamic range... Preferably from pre 1999. If you can get a hold of Pink Floyd "wish you were here" second track or the CD "Division Bell" would be a good choice.
Turn the gain on the amps to as low as they can go. 
Turn up the volume on your HU until you hear distortion, then back it off a tad. Remember where / what number the volume is at. Now turn the gain on the amp until it's starting to distort, then back it back a tad. This will be maximum volume you can play on most material. 

I have 2 two channel 50 watts per channel early 1990's Blaupunkt velocity a amps and a cheap all in one bandpass sub (80 watts RMS) and it can pull 90+ dB (110 + dB from the sub without noticeable distortion) and possibly more, but that is enough for my listening tastes)
Hard to come by but usually go for a decent price. Class A/Business but they never get hot to the touch. 
Good luck,


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## Pimpnyou204

I beleive it comes down to supplying a strong enough and clean signal from the HU and having the headroom to play the dynamic music like orchestras that may have the sharp hits. Turn the volume down and i doubt you can tell much difference, but at the end of the day install is the deciding factor.


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## cleansoundz

An owner of a shop by my house told me that you don't have to spend a lot of money in car audio to get good sound. He had 2 10 inch JL W0v3 woofers sealed, a JL JX 500/1 and JX 360/4 in his acura and it sounded amazing. Those woofers hit hard and his system was clear. He had a Kenwood navigation system and infinity kappa separates. To be honest I cannot hear much of a difference between my JX 1000/1 and slash 1000/1 in bass.


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## brandon.

cleansoundz said:


> An owner of a shop by my house told me that you don't have to spend a lot of money in car audio to get good sound. He had 2 10 inch JL W0v3 woofers sealed, a JL JX 500/1 and JX 360/4 in his acura and it sounded amazing. Those woofers hit hard and his system was clear. He had a Kenwood navigation system and infinity kappa separates. To be honest I cannot hear much of a difference between my JX 1000/1 and slash 1000/1 in bass.


Depends what you consider "a lot of money". The system you're describing easily cost $1000+ (not taking into account any dealer cost discounts, and that's not even really taking into account the cost of the Kenwood navigation).

Some people don't consider this "not a lot of money". Although in my opinion you could probably get a better sounding system for that price.


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## HiloDB1

Waiting for tnbubba to come in here and school us on how there is such a significant difference in sound reproductions between Opamps and class A/B - D amps 
:snacks:


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## Mitsu1grn

Greetings!

Do we really wanna go there with the rolling op-amp test or power supply upgrade debate?

For those of us in the audiophile world who care about more than timbre and head room, we believe that "amps can make a difference" in a system. That being said, when I am searching for an upgrade to my home system or my car system the priority on amplification is this: can it improve my depth of stage, three dimensionality of instruments or people, sense of space and revealing ambience of the recording when listening to classical orchestral recordings.

Those are what I personally listen for when auditioning amplifiers with the Pre-amp that is in my system. Matching pre-amp to an amplifier has always been the most important property when designing a system,( other than the speakers) for me. Some systems work extremely well with less expensive pre-amps mated with a very expensive amp(s) and vice versa. Signatures of certain amplifiers are quite well known in the home audio world, ( McIntosh bass response, Cary Audio SET's using 300B tubes precise three dimensionality, VTL with tremendous staging and imaging with control in the bottom and top end), I can go on.

In car judgement while driving down the highway at 70 MPH probably will not reveal much in terms of Staging and Imaging cues. Granted as a fact. It takes a very quiet venue to reveal the types of cues I am looking for in an amplifier(S) sonic signature. That does not mean that amplifiers do not have certain sonic signatures, they certainly do, at least to my hearing they do. For those of us who are looking for the absolute best in our system, we are in need of the better sound producing amplifiers, ( i.e. Soundstage producing with maximum control over the speakers). Part compliment, power supply design and output devices can make a difference in overall sound. Each section must do its part in a well designed amplifier in order for it to work. 


Nick Wingate


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## feeshta

For a long time I was firmly in the camp of belief that quality being above a certain standard, an amp is an amp for all intents and purposes, and believed in the Richard Clark mentality. Then something happened that made me question this. 

years back I had a 2002 GTI. I had the amp rack and subwoofer enclosure built into the spare tire well, and I had my tusty McIntosh MC431 4x100 watt amplifier intalled there. That thing was huge, and I barely managed to fit it in. It was running pretty hot, and I was afraid I was going to toast the thing or the sub amp that was under it, so I made the decision to go with a smaller amp that would allow me to add some cooling fans etc and get a bett overall cooling solution in place. So, I went to the local store where I was stationed at the time, and was looking for something that fit the bill. Talking to the lead installer there, we somehow got talking about the new at the time US Amps TU series of tube hybrids. He said he was hearing really good things about them, but never had one in the shop to try. Long story short, he offered me a deal (dealer cost) on one provided I allow him a good look at the thing once it came in and give him the job of doing some kickpanels I was looking for an installer on. 

The amp I got is the TU-600. 150 watts by 2. I was just hoping that it wouldn't be too much of a step down in sound quality from the McIntosh. I swapped the two amps out, with the only difference in setup being that I went from bi-amped to a normal setup on my front stage. I was using the passive MB Quart crossovers in both setups, and the front stage was MB Quart Qs. 

So I get done with the job, pop in Dave Matthews Band's under the table and dreaming to take a listen, and was absolutely shocked by what I heard. Those first snare drum shots actually made me flinch they were so fast and direct. Transient response was just worlds better across the board and it sounded as if I had gained power rather than lost. I was amazed. There are a few things I have noticed about this amp that are just different than a normal amp. For example, you can't mess with the speaker wires while the amp is playing. It will actually arc visibly if you do, even at lower volumes. It also runs very very hot, but seems to like it that way. You could literally cook on the thing 

I honestly don't know why this amp sounds so much different, and in my opinion, better. It just does. I recently purchased a TU-4360 to pair with the TU-600 when I get time to finish a system in my current car. 

Like I said, I used to believe they were all the same. I don't anymore.


----------



## MarkZ

It might sound different because you have more power now. That can definitely have an impact on transients the way you describe. Biamping doesn't really gain you much power. It makes things run cooler because you're increasing the impedance of the load (that's what a passive crossover does...). You were still maxed out at 100w with the McIntosh.


----------



## feeshta

MarkZ said:


> It might sound different because you have more power now. That can definitely have an impact on transients the way you describe. Biamping doesn't really gain you much power. It makes things run cooler because you're increasing the impedance of the load (that's what a passive crossover does...). You were still maxed out at 100w with the McIntosh.


I don't think you are seeing things correctly here. Bi-amping does not change the impedance signifigantly when you are using a passive cross-over. In the overlap region between the two transducer's ranges you might have some effect, but over the majority of the frequency response range the amp will still effectively see one transducer or the other, not both. The Q's crossovers have a jumper system to ensure proper impedance matching as well. Passive networks do have some loss, but the loss would have been equal for the two setups, or at least very very close to equal. MB Quart does know what they are doing after all. 

The Mcintosh was running all 4 100 watt channels into the set. 2 on the tweets, two on the mids. Total input received by the Q's would actually be in the range of 570-580 watts, as I had the McIntosh bench tested when I first got it and it ran 144 x 4 cleanly at 4 ohms. This in comparison to the TU-600 which is rated at 2 x 150 into 4 ohms for a total of around 300 watts into the set. I've never had a chance to get it bench tested, since I don't work in a place with a test bench anymore. 

Either the TU-600 was drastically under-rated on power output, or there is something simply different going on.


----------



## MarkZ

cajunner said:


> Also, if every amplifier sounded the same, why would any of these esoteric designers include high dollar parts in their bill of materials? Wouldn't they just spec the cheapest stuff around the Chinese markets, and maximize their profit margin?


For reliability, usually.

Every scientific paper I've read that examines the route to take to create the lowest distortion amplifier has NEVER made mention of parts "quality". It's always about the circuit. You can actually make the tolerance of a part completely unimportant if you design the circuit correctly.


----------



## MarkZ

feeshta said:


> I don't think you are seeing things correctly here. Bi-amping does not change the impedance signifigantly when you are using a passive cross-over. In the overlap region between the two transducer's ranges you might have some effect, but over the majority of the frequency response range the amp will still effectively see one transducer or the other, not both.


We're saying the same thing, so if I'm incorrect then so are you. 

An amp doesn't "see" anything. When you say that the amp doesn't "see" the tweeter anymore, the only difference is that the tweeter is no longer presenting a load to the amp at high frequencies. Therefore, the impedance at 5kHz is no longer the 4 ohm impedance of the tweeter. It's now infinity ohms. Or, more precisely, it's the impedance that the passive crossover + woofer is presenting to the amplifier at 5kHz (perhaps hundreds of ohms...).

So, yes, biamping DOES in fact change the effective impedance of the load. This isn't a matter of insertion loss. It's all about how a passive crossover works!




> The Mcintosh was running all 4 100 watt channels into the set. 2 on the tweets, two on the mids. Total input received by the Q's would actually be in the range of 570-580 watts, as I had the McIntosh bench tested when I first got it and it ran 144 x 4 cleanly at 4 ohms.


And this gets back to what I said to you in my last reply...

4x100 to power a pair of woofers and tweeters means that each woofer has a maximum of 100w available to them. Obviously the tweeters are going to require much less power. When you use a 150x2 amp, it means that each woofer now has 150w minus whatever the tweeters require. In the end, it probably doesn't amount to a huge difference. But it would be interesting to see what the actual numbers were here. You say that the McIntosh was actually capable of delivering 144w (under what conditions?)... I wonder what the other amp was doing?

Anyway, the point is that it's hard to identify what's going on when you don't control for these differences between amps. I don't doubt that you heard a difference, but the big question is: what is the source of the difference? You can't conclude that one amp is inherently more transient than the other amp without first showing that the difference can't be explained by something much more obvious... for example, differences in power, or differences in crossover parameters, etc.


----------



## Richv72

I think amp manufacturers have run out of actual ways to make the amps sound better, so now they are just making them more powerful and adding a bunch of extra crap to them for processing. Although the quality of the parts used seem to be worse on the new amps, chinese and korean generic parts.


----------



## MarkZ

Which parts are you talking about?


----------



## feeshta

MarkZ said:


> We're saying the same thing, so if I'm incorrect then so are you.
> 
> An amp doesn't "see" anything. When you say that the amp doesn't "see" the tweeter anymore, the only difference is that the tweeter is no longer presenting a load to the amp at high frequencies. Therefore, the impedance at 5kHz is no longer the 4 ohm impedance of the tweeter. It's now infinity ohms. Or, more precisely, it's the impedance that the passive crossover + woofer is presenting to the amplifier at 5kHz (perhaps hundreds of ohms...).
> 
> So, yes, biamping DOES in fact change the effective impedance of the load. This isn't a matter of insertion loss. It's all about how a passive crossover works!
> 
> 
> 
> 
> And this gets back to what I said to you in my last reply...
> 
> 4x100 to power a pair of woofers and tweeters means that each woofer has a maximum of 100w available to them. Obviously the tweeters are going to require much less power. When you use a 150x2 amp, it means that each woofer now has 150w minus whatever the tweeters require. In the end, it probably doesn't amount to a huge difference. But it would be interesting to see what the actual numbers were here. You say that the McIntosh was actually capable of delivering 144w (under what conditions?)... I wonder what the other amp was doing?
> 
> Anyway, the point is that it's hard to identify what's going on when you don't control for these differences between amps. I don't doubt that you heard a difference, but the big question is: what is the source of the difference? You can't conclude that one amp is inherently more transient than the other amp without first showing that the difference can't be explained by something much more obvious... for example, differences in power, or differences in crossover parameters, etc.


The testing parameters were the standard test bench procedure our shop tech used. I believe it was running pink noise into a 4 ohm dummy load and averaged over a 15 minute run, but it's been quite a few years. The McIntosh had a built in limiting circuit that would automatically cut the gain when it sensed distortion, so there was no setting anything there, just turn up the souce until the indicator had just turned on and leave it there. The McIntosh actually came with a "birth certificate" test result showing 138 watts from the company. I was curious and had them test it in the shop to see if they got the same result. 

Either way, we are not talking about enough of a difference in power to produce such viscerally stunning differences. you would have to more than double power to achieve a similar change, and the change is apparent at all listening volumes, not just when driven hard. It was absolutely night and day difference. Not a "little better". It was as if we had replaced the drivers themselves completely. Brighter, much more immediate, totally different presence.


----------



## Richv72

MarkZ said:


> Which parts are you talking about?


Well, capacitors for one.


----------



## MarkZ

cajunner said:


> I would have to disagree somewhat, but not that much, haha..
> 
> of course, I like marketing jargon too.
> 
> but I believe that the upgrades in parts from the lower end lines to higher spec, higher cost models is not simply reliability, it's consistency in the circuit doing what it's supposed to do, over time and temperature and operating variables.
> 
> I think tolerance is always important, if keeping with the circuit design is important, because hitting a specification out of tolerance but still operational, means an amp will have a vulnerability.


Not if you design the circuit to have a wide tolerance. For example, you can build a typical transconductance stage in the amplifier with a 10-fold range in current before you begin to degrade the signal. All else being equal, that would mean you could use any resistor you want within 1k - 10k.  Or maybe a better example... if you design input stage circuits to use current mirrors instead of pulldown resistors, you can use (almost) whatever the hell value of resistances you want. It's actually customary when designing circuits of any type to make the beta value of your transistor meaningless... which is interesting, since at first glance, beta is the most important transistor parameter. 

You're right that changes in parameters with temperature is a HUGE issue, but again, if you design the circuit correctly and cleverly you can mitigate those issues. So, instead of hunting for the perfect transistor that has the right temperature behavior, and then trying to match all the transistors to have that same behavior, you could simply build a circuit that compensates for this temperature dependence (e.g. a properly constructed self-biasing circuit in an output stage).

Where's the difficulty here? Usually parts count. Sometimes you have to triple or quadruple your parts count just to achieve a 20% reduction in distortion. A lot of times it's all small signal parts, but still... Manufacturers usually don't go for that.


----------



## RNBRAD

feeshta said:


> The testing parameters were the standard test bench procedure our shop tech used. I believe it was running pink noise into a 4 ohm dummy load and averaged over a 15 minute run, but it's been quite a few years. The McIntosh had a built in limiting circuit that would automatically cut the gain when it sensed distortion, so there was no setting anything there, just turn up the souce until the indicator had just turned on and leave it there. The McIntosh actually came with a "birth certificate" test result showing 138 watts from the company. I was curious and had them test it in the shop to see if they got the same result.
> 
> Either way, we are not talking about enough of a difference in power to produce such viscerally stunning differences. you would have to more than double power to achieve a similar change, and the change is apparent at all listening volumes, not just when driven hard. It was absolutely night and day difference. Not a "little better". It was as if we had replaced the drivers themselves completely. Brighter, much more immediate, totally different presence.


"Viscerally stunning difference" Interesting comment  I have never experienced such a difference among high quality amps. My only thought would be that your new amp somehow adultered the sound and somehow this was to your liking. This would not be the first time a piece of equipment skewed or adultered (distorted in other words) a clean signal and then it was perceived as being of better sound quality. IMO, I feel that's the case here. If it's not, then something else happened. Reason I say that, I've used Mcintosh since mid 90's and they are the gold standard in transparency, meaning they do not have an audible signature or no "character" like some amps do. They add nothing and do a better job at that then virtually any amp manufacturer out there. Some people like that, some don't.


----------



## MarkZ

cajunner said:


> yes, I forgot that, good point.
> 
> so, Luxman. They have this big amp, 100W/ch and it's filled with small circuit parts.
> 
> this must be what you mean, because it's got low distortion.
> 
> 
> now, conversely, Linear Power.
> 
> they have a simple little circuit, wide open small signal parts layout, and supposed extremely low distortion.
> 
> would this be a case of matching transistors and careful/tight tolerance bias current, or is it the marketing?
> 
> would you find DC offset more of a problem in a low parts count, high quality parts/high cost parts, amplifier, or....
> 
> 
> would you find it more likely in a high parts count, cheap parts amplifier?
> 
> 
> and, where would you place a Brax in relation to small signal parts count?
> 
> if the circuit can be made with lower parts count, and you need higher labor costs to tune the parts to the circuit, that would seem to be where Linear Power got it's start.
> 
> using the big metal can T-03 transistors should have provided an easier matching, I am guessing because it's harder to pop a transistor that has some heat sink built into it. Also, the reliability of these type of transistors met mil-spec requirements and came relatively well matched from the supplier.
> 
> 
> does this sound reasonable for speculative purposes?



There might be some truth to that. I hadn't really thought of it that way.

But there are some things that just can't be "tuned", where more complex circuitry can come in and improve. Protection circuitry is probably the most obvious of these. But, regarding "sq", there are lots of modifications in the first stage of an amp that can be incorporated to reduce THD and noise dramatically. For example, buffers (transistor circuits) between the signal path and the supply rails can improve PSRR significantly; distortion performance can be improved by using a more sophisticated differential stage; I've even seen a design that literally DOUBLED the size of the input stage and configured it into two push-pull arrangements for a relatively modest decrease in THD. I'm sure manufacturers are saying, "double parts count to go from .01% to .005%? Aw hell no."


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## Mitsu1grn

Greetings!

I normally don't get involved with this topic when it comes up from time to time, but in this case I am going to make a statement regarding the "all amps sound the same" statement.

In the world of car audio, there is not a whole lot of difference in amps SQ as far as power or THD is concerned, (We can dispense with the Class AB or D discussion for another day). In car audio there are amps that can present a different sound stage than other amps. For instance, the Mosconi Class A or Zero1 amps do present a more three dimensional sound stage than the Mosconi AS series of amps do. I can personally attest to that. Do they "SOUND" different? In a word, yes, but in my experience where amps differ is in three dimensionality of instruments and/or people within the sound stage. This is revealed mainly in High Resolution recordings that I listen to, specifically Classical Music. 

Reference Recordings has a number of 24bit/192Khz recordings that you can buy on line and they do reveal how good or how bad the system you have is in terms of soundstage reproduction. The only caveat in this is your system in your car needs to be able to recreate a soundstage and that means imaging and staging. If your car does not do this I doubt you would hear a difference in those amplifiers or any amplifiers of decent quality.

Home Audio is a different animal all together. The difference between tubes and solid state is huge. So is pure class A and class AB or class T amps. Major difference in designs, such as the Mcintosh solid state using the Autoformers and not using the Autoformers. Krell FPB design versus the HTS design. Big difference in sound! VTL tubes at 1200 watts per channel mono blocks with external power supplies, wanna hear something really incredible? These will do it! 

There are differences in amps in my opinion. My ears tell me so. Whether or not anyone cares to take the time and set up a high enough reference system that can reveal the differences, that is a discussion for another time!'

Nick Wingate


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## MarkZ

Mitsu1grn said:


> In car audio there are amps that can present a different sound stage than other amps. For instance, the Mosconi Class A or Zero1 amps do present a more three dimensional sound stage than the Mosconi AS series of amps do. I can personally attest to that. Do they "SOUND" different? In a word, yes, but in my experience where amps differ is in three dimensionality of instruments and/or people within the sound stage. This is revealed mainly in High Resolution recordings that I listen to, specifically Classical Music.


How, exactly, does an amp impart spatial information? It has two channels. Again, its operation can be described by its frequency response, its distortion, and its noise properties -- all three of which can have an impact on spatial audio (people usually even manipulate two of those things purposefully to change the spatial response of their system). 

Crosstalk is another factor that can influence spatial information, but I'm not aware of any amps in car audio whose crosstalk is so bad that it has any appreciable impact.

So what I suspect you're hearing is related to what the others have mentioned... frequency response and dynamics. And these are measurable quantities that, fortunately, we can also tailor outside the realm of amplification.


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## Hillbilly SQ

My amps have essque fairydust in them. Makes me feel all warm and fuzzy inside.


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## Hillbilly SQ

And for the record I am a firm believer in buying quality equipment. If an amp has quality close tolerance parts in it you will most likely get longer life and a more UNAUDULTERATED sound out of it. BTW, MOST of my listening is done with the engine OFF. Driving with music playing breaks my concentration. Because of my listening habits an amp CAN have a noticable effect on the sound. I've heard it and no one can convince me otherwise so don't even try to tell me different. If I did all my listening while driving I agree I likely wouldn't be able to tell the difference between a class d, $100 fleamarket amp, and $1000 high end amp. I'm NOT in that blanket category.


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## MarkZ

Hillbilly SQ said:


> And for the record I am a firm believer in buying quality equipment. If an amp has quality close tolerance parts in it you will most likely get longer life and a more UNAUDULTERATED sound out of it.


This is a myth. I already addressed this. :worried:


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## Hillbilly SQ

Didn't one of the Blues comp cars have a processor hidden in it? I heard it was the only one on the team that actually did good when all the marbles were at stake. Now while I agree that speaker placement can make a huge difference in how the finished tune sounds but I just don't see how a car set up and tuned in 1980's fashion could even begin to compete with todays installs with the processing that's out today. I will admit though that when I put a 6.5" in my doors that was capable of passing the 5k mark without noticable beaming they actually sounded coherent right out of the gate without time alignment. This is low in the doors in a Ram so there was still likely a couple feet in pathlength difference. But to manipulate the stage there's no way around using a processor short of the "perfect" install. Does that even exist in car audio?


----------



## ChrisB

Hillbilly SQ said:


> Didn't one of the Blues comp cars have a processor hidden in it? I heard it was the only one on the team that actually did good when all the marbles were at stake.


So now they are resorting to hidden processors after their strict rule of not allowing digital processing?:laugh:

Oh well, it could be like jimmy2345 commenting on Randall's truck saying that he was winning competitions with no processing... There was a modified Linear Power Crossover and Equalizer right below the radio. I think that was the year Randall took first at all the local competitions and finished either dead last or second to last at world finals.



Hillbilly SQ said:


> Now while I agree that speaker placement can make a huge difference in how the finished tune sounds but I just don't see how a car set up and tuned in 1980's fashion could even begin to compete with todays installs with the processing that's out today. I will admit though that when I put a 6.5" in my doors that was capable of passing the 5k mark without noticable beaming they actually sounded coherent right out of the gate without time alignment. This is low in the doors in a Ram so there was still likely a couple feet in pathlength difference. But to manipulate the stage there's no way around using a processor short of the "perfect" install. Does that even exist in car audio?


The most limiting factor to car audio is the car itself. Once you take that out of the equation, the rest is easy.

Even processing has its drawbacks. I noticed that digital time alignment can cause weird phasing issues with new age music that has a lot of spatial enhancement. For some reason, delaying the signal does not net the same effect as proper equidistant positioning of the speakers like in a home or studio environment.


----------



## feeshta

ChrisB said:


> So now they are resorting to hidden processors after their strict rule of not allowing digital processing?:laugh:
> 
> Oh well, it could be like jimmy2345 commenting on Randall's truck saying that he was winning competitions with no processing... There was a modified Linear Power Crossover and Equalizer right below the radio. I think that was the year Randall took first at all the local competitions and finished either dead last or second to last at world finals.
> 
> 
> 
> The most limiting factor to car audio is the car itself. Once you take that out of the equation, the rest is easy.
> 
> Even processing has its drawbacks. I noticed that digital time alignment can cause weird phasing issues with new age music that has a lot of spatial enhancement. For some reason, delaying the signal does not net the same effect as proper equidistant positioning of the speakers like in a home or studio environment.


With a resonant, repetitive kind of sound, you might notice some comb filtering type effects due to interaction with the environment. While the signals are delayed to reach the driver's ears at the same time, they are in fact still slightly out of phase from the standpoint of their interaction with the car. With normal music you would never be able to hear this, but with a constant droning tone, it might become audible. It's basically a smaller scale demonstration of the type of interaction that creates the "wub wub" sound in dubstep music. 

Of course, actually listening to that newage crap is the actual problem in my opinion, but to each his own. :laugh:


----------



## Danometal

LOLZ @ "wub wub!!!!"

I tried to not hate dubstep a couple times. Didn't work. It just sucks to hear such offensive sounds on purpose, so I listen to pleasant sounds instead. 

/subjective arbitrary comment


----------



## Hillbilly SQ

feeshta said:


> With a resonant, repetitive kind of sound, you might notice some comb filtering type effects due to interaction with the environment. While the signals are delayed to reach the driver's ears at the same time, they are in fact still slightly out of phase from the standpoint of their interaction with the car. With normal music you would never be able to hear this, but with a constant droning tone, it might become audible. It's basically a smaller scale demonstration of the type of interaction that creates the "wub wub" sound in dubstep music.
> 
> Of course, actually listening to that newage crap is the actual problem in my opinion, but to each his own. :laugh:


I've had comb filtering at around 8khz in both of my Rams (09 and 11). Both have had identical interiors but the one I have now is a different color and quite the beast compared to the underpowered 09 I had. Too much truck for a small v8 imo. Anyway, frequency centered pink noise at around 8khz triggers comb filtering every time. I did notice that the overall coherence of the sound is much better with my door speakers playing up to 5khz. Amazing what keeping the meat and potatoes of the vocal range confined to one pair of drivers will do. It's nice having something that can go that high cleanly without noticable beaming. Now I know what the HAT guys have been raving about. Oh crap, I'm gonna catch hell for saying that after all the **** I've talked about that not being possible out of a 6.5" driver off axis:laugh:I'm tempted to give the new tweeters Audible Physics is coming out with a shot mounted on top of the dash Kirk Proffit style. Also need to at some point pull the grills off my dash to see if they're causing the comb filtering.


----------



## ChrisB

feeshta said:


> With a resonant, repetitive kind of sound, you might notice some comb filtering type effects due to interaction with the environment. While the signals are delayed to reach the driver's ears at the same time, they are in fact still slightly out of phase from the standpoint of their interaction with the car. With normal music you would never be able to hear this, but with a constant droning tone, it might become audible. It's basically a smaller scale demonstration of the type of interaction that creates the "wub wub" sound in dubstep music.
> 
> Of course, actually listening to that newage crap is the actual problem in my opinion, but to each his own. :laugh:


When I mention "new age" I'm talking about world fusion or new age relaxation music... You know, stuff like Enya, Dead Can Dance, Enigma, and things along those lines.

By no means does Dubstep qualify as new age. In fact, it is nothing "new" at all... In the 90s, a familiar technique was for club music to slow down to half time during a break down in the song. Dubstep is essentially that half tempo combined with a drum and bass style riff. That gets all the youngster's up and arms when I tell them that it is nothing new, then show them. French Kiss by Lil Louis was probably the first popular dubstep style breakdown back in 1989.:laugh:


----------



## feeshta

ChrisB said:


> When I mention "new age" I'm talking about world fusion or new age relaxation music... You know, stuff like Enya, Dead Can Dance, Enigma, and things along those lines.
> 
> By no means does Dubstep qualify as new age. In fact, it is nothing "new" at all... In the 90s, a familiar technique was for club music to slow down to half time during a break down in the song. Dubstep is essentially that half tempo combined with a drum and bass style riff. That gets all the youngster's up and arms when I tell them that it is nothing new, then show them. French Kiss by Lil Louis was probably the first popular dubstep style breakdown back in 1989.:laugh:


I wasn't saying you like Dubstep, or thinking that was what you were referring to. Simply stating that the type of effect that creates the sound effects in dub-step is similar to the interaction of direct and reflected sound that creates the effect you hear in your car when listening to your new-age stuff, just on a far larger scale. 

The dubstep sound effects are created by the interaction of two different signals, and by controlling different aspects of those signals to create different effects and frequencies. The effects used to create a sense of space in new age music essentially simulate the echo signature of a large interior space. The interaction of that effect with the natural sound-reflective profile of your car interior, and combined with the slightly out of phase situation created by the delay, creates an interaction of the signals that is audible. It's only going to be audible in a situation where you have a signal that stays near constant, like what you get in new age music like Enya. 

I'm not a big fan of new age though, sorry.


----------



## cobraa

Hu for sure!


----------



## Golden Ears

ChrisB said:


> It is amazing what people will believe because they want to believe. I used to fall into that category myself, until I noticed that I couldn't tell the difference between old school, new school, and full-range class D in a moving car. So either I'm tone deaf or others believe in SQ fairies and SQ unicorns.
> 
> Regardless, I am happy that I came to my senses and chose to approach my car audio projects from a more scientific perspective. Since then, I managed to save a lot of money, headache, and grief. I just feel sorry for those who haven't come around and still believe in tuning their system via amplifier swapping. Poor people, they are destined to be forever parted from their hard earned money.


Yes SQ can be achieved in a car, BOSE has already achieved the highest possible quality. Trying to use better amps is useless in such a hostile environment. In fact I can not even hear the difference between the BOSE upgrade and the base stock system, maybe just a bit more bassy with Bose.

To save real money, you can just wear headphones and sing along for the others and they will hear live music in the car, but they won't recognize your voice in the car because the environment is so bad.

I swapped all these audio systems into my top fuel dragster... And even tested without wearing hearing Protection. ...I can not hear the difference, in fact, I can't hear much of anything.


Bose knows. He went to MIT and they must know the most because of all the science and because they are a big company that has the facilities to make the best.


In audio, some things can not be explained.........to everyone.

Of course this is sarcasm.


----------



## Danometal

Golden Ears said:


> Yes SQ can be achieved in a car, BOSE has already achieved the highest possible quality. Trying to use better amps is useless in such a hostile environment. In fact I can not even hear the difference between the BOSE upgrade and the base stock system, maybe just a bit ore bass with Bose.
> 
> To save real money, you can just wear headphones and sing along for the others' and they will hear live music in the car, but they won't recognize your voice in the car because the environment is so bad.
> 
> I fit them all into my top fuel dragster... And even tested without wearing hearing Protection. ...I can not hear the difference, in fact, not I can't hear much of anything.
> 
> 
> Bose knows. He went to MIT and they must know the most because of all the science and because they are a big company that has the facilities to make the best.
> 
> 
> In audio, some things can not be explained.........to everyone.
> 
> Of course this is sarcasm.


LOLZ :laugh:

Classic.


----------



## feeshta

rain27 said:


> I agree. I meant that I don't think the sq amp could be determined whether in a quiet room or noisy car.
> 
> All of the tests so far have been in ideal listening environments and still no one in the history of amps has been able to distinguish one from another.
> 
> Not sure what other compelling evidence people need. But an amp test with car audio amps would strengthen what's already been established.
> 
> Whoever administers the test will be referred to for years when people remember the test where no one could distinguish the Tru amp from the Kenwood.


When you pull a Richard Clark and set unrealistic thresh-holds for comparing the two devices in order to ensure that no difference can be perceived, then of course you will not be able to tell the difference. 

The differences come at high listening volumes, when the speakers become a much more reactive load and more difficult to control. The more power you throw at a speaker, the more it talks back and tries to disobey. This isn't an issue at "reference" levels. At reference levels, the two amplifiers will not be outputing much more than a watt of power. It's an idiotic test, although it does prove a point. If you don't listen loud, then don't bother with big power or high end amplification because there will be no benefit. 

High quality amplification with plenty of power may be even more important in the car environment than in the home. This is due to the higher levels of background noise, and the greater levels of output required to overcome this obstacle. This is particularly true with subwoofer type frequencies, due to the predominance of low frequency road noise. 

It's at higher output levels that the differences become obvious. If someone made a low-end, inexpensive amp that could actually deal with a reactive load and supply plenty of power, then the idea would be valid. But I haven't seen them yet. Let me know if you do.


----------



## MarkZ

feeshta said:


> When you pull a Richard Clark and set unrealistic thresh-holds for comparing the two devices in order to ensure that no difference can be perceived, then of course you will not be able to tell the difference.


How are they unrealistic? This is what you do to isolate variables. You introduce an artifice so that you can test the particular hypothesis you're trying to test. The challenge was never intended to demonstrate that all amps sound the same. The challenge's intent was to demonstrate that all amps _can be made to sound the same_. Those that don't understand the importance of this demonstration are not aware of the context from which it arose. The subjectivist movement always centered around the idea that they cannot be made to sound the same. Once that question is answered, you can then objectively determine which factors contribute to the differences between amps -- simply by undoing the changes you had to make to make them sound the same! That's why this test is useful.

Without RC's challenge, we might still be in the dark ages arguing over the magical properties of amplifiers that make them so intrinsically different that no amount of measurement could ever reveal how they're different. And yes, there are some people who believe that.


----------



## feeshta

MarkZ said:


> How are they unrealistic? This is what you do to isolate variables. You introduce an artifice so that you can test the particular hypothesis you're trying to test. The challenge was never intended to demonstrate that all amps sound the same. The challenge's intent was to demonstrate that all amps _can be made to sound the same_. Those that don't understand the importance of this demonstration are not aware of the context from which it arose. The subjectivist movement always centered around the idea that they cannot be made to sound the same. Once that question is answered, you can then objectively determine which factors contribute to the differences between amps -- simply by undoing the changes you had to make to make them sound the same! That's why this test is useful.
> 
> Without RC's challenge, we might still be in the dark ages arguing over the magical properties of amplifiers that make them so intrinsically different that no amount of measurement could ever reveal how they're different. And yes, there are some people who believe that.


They are unrealistic because they have no relevance to how people actually listen to their music. They are specifically designed to remove differences that impact the listening experience. 

It's an interesting test, and it does prove a point, but it's idiotic to think that all amps are created equal. They simply are not. 

To be clear, I am not argueing that some amps are "magical" or have a different sound. Simply that some amplifiers sound better because they exercise more power of the louspeakers at high listening volumes, a fact that is completely ignored by Mr. Clark's test. If you are listening to Bach at a moderate volume then you are probably fine with junk. If you are listening to Tool at near concert levels, good luck with that cheap amp. It's going to sound like crap.


----------



## putergod

I've said this before and I will say it again.

RE: dipsh!t clark's challenge: If a crap load of processing, or anything similar, must be done in order to make two amps sound alike...
then...
those two amps do NOT sound alike!

Similarly,
If something supposedly "tastes good" but is an "aquired taste" then it does NOT "taste good".


----------



## MarkZ

feeshta said:


> They are unrealistic because they have no relevance to how people actually listen to their music. They are specifically designed to remove differences that impact the listening experience.
> 
> It's an interesting test, and it does prove a point, but it's idiotic to think that all amps are created equal. They simply are not.
> 
> To be clear, I am not argueing that some amps are "magical" or have a different sound. Simply that some amplifiers sound better because they exercise more power of the louspeakers at high listening volumes, a fact that is completely ignored by Mr. Clark's test. If you are listening to Bach at a moderate volume then you are probably fine with junk. If you are listening to Tool at near concert levels, good luck with that cheap amp. It's going to sound like crap.


I get what you're saying, but could you explain the nonlinearity you're talking about? Most amplifiers tend to exhibit _lower_ distortion as output rises, not higher (at least until you begin to approach clipping). The speaker is also going to be less reactive at higher output levels due to power compression (the ratio of reactive to resistive gets lower). Yes, motional EMF increases with cone motion, but so does output voltage (actually, at a somewhat lower rate of increase than output voltage, due again to power compression). So it's not clear to me how the differences in most amps will appear more prominent at higher levels.


----------



## MarkZ

putergod said:


> I've said this before and I will say it again.
> 
> RE: dipsh!t clark's challenge: If a crap load of processing, or anything similar, must be done in order to make two amps sound alike...
> then...
> those two amps do NOT sound alike!


Wow. Talk about missing the point.



> Similarly,
> If something supposedly "tastes good" but is an "aquired taste" then it does NOT "taste good".


The better analogy would be this:

One chef cooks a meatloaf and charges you $6 for it. Another very highly paid chef cooks a meatloaf that tastes different from the first chef's. He charges you $40. However, if it could be shown that adding the right amount of salt to the cheap meatloaf could make it taste exactly like the expensive meatloaf, it would be worth knowing.


----------



## putergod

MarkZ said:


> Wow. Talk about missing the point.
> 
> 
> 
> The better analogy would be this:
> 
> One chef cooks a meatloaf and charges you $6 for it. Another very highly paid chef cooks a meatloaf that tastes different from the first chef's. He charges you $40. However, if it could be shown that adding the right amount of salt to the cheap meatloaf could make it taste exactly like the expensive meatloaf, it would be worth knowing.


Right... So, spending a fortune, and Gods knows how many man hours tweaking processors, just to make a piece of crap sound simiar to a quality piece of equipment, excuses the piece of crap for being a piece of crap, and therefore worth buying over the quality piece of equipment that doesn't need processing to sound good? 
I don't think so...

And note, a "watt" =! a "watt+processing". Therefore, as stated before, not all watts are created equal. Never have been, and almost certainly never will be.

So again, his so-called "challenge" is nothing more than just a "sham".
You put a Carver Silver 7 next to an equally "powerful" Audiovox purchase at Radio Shack, without molesting the inputs or outputs, and there will be a DRASTIC difference in sound!


----------



## MarkZ

putergod said:


> Right... So, spending a fortune, and Gods knows how many man hours tweaking processors, just to make a piece of crap sound simiar to a quality piece of equipment, excuses the piece of crap for being a piece of crap, and therefore worth buying over the quality piece of equipment that doesn't need processing to sound good?
> I don't think so...


That's where the "missing the point" thing comes in, because I already addressed that point two posts ago. It's not about "excusing the piece of crap." It's about identifying what the differences are between two amps. That's important, even if you don't think so. There's a large contingent of people that believe that you cannot actually describe the differences between amps in any linear systems way. For example, you, in the next line:



> And note, a "watt" =! a "watt+processing". Therefore, as stated before, not all watts are created equal. Never have been, and almost certainly never will be.





> So again, his so-called "challenge" is nothing more than just a "sham".
> You put a Carver Silver 7 next to an equally "powerful" Audiovox purchase at Radio Shack, without molesting the inputs or outputs, and there will be a DRASTIC difference in sound!


If this is so, then it would be neat to see this accomplished. RC's challenge allows you to attempt to do this. What is your objection?


----------



## BuickGN

putergod said:


> Right... So, spending a fortune, and Gods knows how many man hours tweaking processors, just to make a piece of crap sound simiar to a quality piece of equipment, excuses the piece of crap for being a piece of crap, and therefore worth buying over the quality piece of equipment that doesn't need processing to sound good?
> I don't think so...
> 
> And note, a "watt" =! a "watt+processing". Therefore, as stated before, not all watts are created equal. Never have been, and almost certainly never will be.
> 
> So again, his so-called "challenge" is nothing more than just a "sham".
> You put a Carver Silver 7 next to an equally "powerful" Audiovox purchase at Radio Shack, without molesting the inputs or outputs, and there will be a DRASTIC difference in sound!


Maybe, maybe not. The real eye opener came when I substituted a borrowed $100 Interfire amp when I had to remove my McIntosh for a few days and could not hear a difference. After a month of swapping these amps back and forth along with the HD 900/5 I ended up with the HDs, not exactly the most expensive amps out there but every bit as good in SQ and with several advantages.


----------



## putergod

MarkZ said:


> If this is so, then it would be neat to see this accomplished. RC's challenge allows you to attempt to do this. What is your objection?


He won't allow it. His psuedo challenge involes allow him to using processing until he feels that he has made both "systems" (I say systems because it is much more than "amp vs amp" when the processors are involed) sound as close to the "same" as he can with the processors he is using. At no point is he willing to pony up the dough if you want to just compare two amplifiers of significant "quality difference" on the same reference quality speakers with the same reference material completed un-modified.


BuickGN said:


> Maybe, maybe not. The real eye opener came when I substituted a borrowed $100 Interfire amp when I had to remove my McIntosh for a few days and could not hear a difference. After a month of swapping these amps back and forth along with the HD 900/5 I ended up with the HDs, not exactly the most expensive amps out there but every bit as good in SQ and with several advantages.


My real eye opener was when I temporarily substituted my SoundStream for a cheap amp to get a dual diode replaced. The difference was so drastic I didn't even want to tun the radio on during that time!


cajunner said:


> the pixie dust in McIntosh amps is blue, HD has the gray stuff..
> 
> Interfire, well they put in some white.


And Mmats uses the red stuff.......

It's the QUALITY of pixie dust that matters!


----------



## Danometal

I have entry level Boston GTA amps, and they sound as good to my ears as any other amps I've heard. I think any notable differences in sound is really the speakers doing the talking.

That said, I won't buy any amp whose RMS power is overrated, or even if it's rated by its MAX power. Something about that gives me a rash, and I'll keep looking for something more honest.


----------



## MarkZ

putergod said:


> You put a Carver Silver 7 next to an equally "powerful" Audiovox purchase at Radio Shack, without molesting the inputs or outputs, and there will be a DRASTIC difference in sound!





putergod said:


> He won't allow it. His psuedo challenge involes allow him to using processing until he feels that he has made both "systems" (I say systems because it is much more than "amp vs amp" when the processors are involed) sound as close to the "same" as he can with the processors he is using. At no point is he willing to pony up the dough if you want to just compare two amplifiers of significant "quality difference" on the same reference quality speakers with the same reference material completed un-modified.


Oh the irony! Bob Carver's whole schtick in the 80's was to design amps that basically had "processing" to try to mimic other amps. :laugh:


----------



## putergod

MarkZ said:


> Oh the irony! Bob Carver's whole schtick in the 80's was to design amps that basically had "processing" to try to mimic other amps. :laugh:


You are about 5% correct and 95% incorrect.
First, Bob Carver did NOT use "processors" in his amps. They were all DESIGNED to sound the way he made them sound.
Second, Bob Carver did NOT try to "mimic other amps". What he did was try to mimic his OWN amp in a solid state design.
Did he achieve this? I don't think so. But he did get pretty dang close.

I have a whole stack of Carver amps powering my home theater, and not a single one of them has "processors" in it. And, they are almost all of the TFM series (which are the ones you are referring to).
2x TFM-15c (one powering center, bridged, awaiting another center)
1x TFM-22 (powering rears)
1x TFM-25 (powering sides)
1x TFM-35x (powering subwoofers)
and 1x A500x (powering fronts)


----------



## Hanatsu

I'd be very very interested to actually see some measurements on what's different between all these amps, source units etc. If there is an audible difference, it must be electrical and electrical parameters can be measured. Speakers are measured for distortion/frequency response all the time, why can't someone measure output, FR, distortion, noise from an amp? Is it that hard to do or what... ?? Don't think I've ever seen a detailed distortion measurement of an amp other than occasionally a THD-vs-power graph.


----------



## MarkZ

putergod said:


> You are about 5% correct and 95% incorrect.
> First, Bob Carver did NOT use "processors" in his amps. They were all DESIGNED to sound the way he made them sound.


Note that I put "processor" in quotes.

But answer this: if you put a capacitor in your transconductance path, which is commonly done to alter the distortion-dependence on frequency, -- or if you use an artificially high output zobel or low feedback gain to screw around with output impedance and frequency response -- how is this any different from performing the same manipulations digitally? And if Richard Clark "undoes" these manipulations using signal processing to make the Carver amp achieve the flat response profile that the cheap amp has, how is this any different from bypassing the pre-amp signal processing that a lot of amps have built-in?

Again, I think you lack the context of the amplifier debates that have gone on for decades. If Richard Clark can show that signal processing can eliminate the differences between a $10000000000000 amp and a flea market amp, that's a pretty big ****ing deal right there.



> Second, Bob Carver did NOT try to "mimic other amps". What he did was try to mimic his OWN amp in a solid state design.


His "own" amp _was_ another amp.


----------



## putergod

MarkZ said:


> Note that I put "processor" in quotes.
> 
> But answer this: if you put a capacitor in your transconductance path, which is commonly done to alter the distortion-dependence on frequency, -- or if you use an artificially high output zobel or low feedback gain to screw around with output impedance and frequency response -- how is this any different from performing the same manipulations digitally? And if Richard Clark "undoes" these manipulations using signal processing to make the Carver amp achieve the flat response profile that the cheap amp has, how is this any different from bypassing the pre-amp signal processing that a lot of amps have built-in?
> 
> Again, I think you lack the context of the amplifier debates that have gone on for decades. If Richard Clark can show that signal processing can eliminate the differences between a $10000000000000 amp and a flea market amp, that's a pretty big ****ing deal right there.
> 
> 
> His "own" amp _was_ another amp.


omg... really???
There are no processors in his amps, period (.)! So, you are going to tell me that what crowbar clark does to craptastic junk using external processors (that aren't cheap), and lots of time is even remotely "equivilent" to a very well designed amp, that is designed, from the ground up, to sound very good - which is in complete contrast to how cheap amps are designed and made? That whole thought process doesn't even compute!

Anyone with a brain can easily see how stupid your remarks are. If you chocolate coat a turd, it's still a turd.

I'll give those that work hard to create amps that are very well designed, and very well built, my money. Those companies that produce crap, and then have puppets come on and talk about some idiots "rigged 'challenge'" is the savior and excuser of all things crap, so they do not have to put any real work into their crappy designs can shove it. I don't buy crap.

Learn to compare apples to apples, and not apples to oranges, and you might get a little respect in your 'thoughts'.
amp vs amp is not equal to amp vs amp+processor.

You build a car, you tout that your car is the fastest in the world. Richard Clark tells you that he will bet you 10k to prove that statement in his challenge. His challange is, he gets to use your car while he takes his Civic and does whatever mods he has to in order to make his Civic just as fast as your car - then the "challenge" begins. So you'd take that challenge with 10k on the line?


----------



## MarkZ

putergod said:


> omg... really???
> There are no processors in his amps, period (.)! So, you are going to tell me that what crowbar clark does to craptastic junk using external processors (that aren't cheap), and lots of time is even remotely "equivilent" to a very well designed amp, that is designed, from the ground up, to sound very good - which is in complete contrast to how cheap amps are designed and made? That whole thought process doesn't even compute!
> 
> Anyone with a brain can easily see how stupid your remarks are. If you chocolate coat a turd, it's still a turd.


It's only a turd because you're calling it a turd. RC is demonstrating that it actually _isn't_ a turd. That it's audibly indistinguishable from something you don't call a turd.

Basically, he's challenging your unfounded assertion that something is a turd. So that leaves the burden of proof on you to prove that it's a turd. And you haven't yet been able to present any argument to actually do that, other than to whine "Noooo he's cheating! Altering the frequency response to mimic the reference amp doesn't count!!!"... all while propping up an amplifier design whose stated goal is to alter the frequency response to mimic other amps. :laugh: It's amazing to me that this irony is lost on you.

Edit:


> Learn to compare apples to apples, and not apples to oranges, and you might get a little respect in your 'thoughts'.
> amp vs amp is not equal to amp vs amp+processor.


Four.

That's the number of times I explained in this thread already that RC's amp challenge isn't what you think it is.

Another piece of irony. You think I'm failing to compare apples to apples, but RC's amp challenge has nothing to do with the apples you want so desperately to compare. If you want to talk about amps sounding differently from others because some boutique companies deliberately alter the frequency response and distortion profile to achieve some other goal, then you're not going to find _anyone_ in this thread who has disagreed with that idea.


----------



## putergod

I've read his "challenge", and it is exactly what I am saying it is. You are still chocolate coating turds.



I'm done with you.


----------



## putergod

MarkZ said:


> You think I'm failing to compare apples to apples, but RC's amp challenge has nothing to do with the apples you want so desperately to compare. If you want to talk about amps sounding differently from others because some boutique companies deliberately alter the frequency response and distortion profile to achieve some other goal,


No, what I am talking about is taking two amplifiers, of differeing designs, and compare them, directly, head to head, and you will hear a difference (if there is a large difference in the design and quality of the amps). But no... you want to "moddify","beef up", or whatever term you want, the sound of the inferior product. Basically, you don't want to race until you've inject enough nitrous oxide to make your inferior car as fast as mine. Therefore, if someone is looking for the better car, you try and lie to them that your car is just as fast as mine for much less money - and in the fine print "BUT, you have to purchase this turbo and nitrous kit, and hire a professional driver first".

_Now_, I am done with you.


----------



## MarkZ

putergod said:


> I'm done with you.





putergod said:


> No, what I am talking about is taking two amplifiers, of differeing designs, and compare them, directly, head to head, and you will hear a difference (if there is a large difference in the design and quality of the amps).


Remind me who's disagreeing with you on that point? 



> But no... you want to "moddify","beef up", or whatever term you want, the sound of the inferior product. Basically, you don't want to race until you've inject enough nitrous oxide to make your inferior car as fast as mine. Therefore, if someone is looking for the better car, you try and lie to them that your car is just as fast as mine for much less money - and in the fine print "BUT, you have to purchase this turbo and nitrous kit, and hire a professional driver first".


By definition, the so-called inferior car IS as fast as your awesome car... if it actually achieves the same speed. Whether it uses nitrous or rocket boosters from NASA... doesn't really matter,* if the question is how fast the two cars go. *

If the question is how elegant and cutting-edge your car design is, and how many man-hours were invested in getting it there, and how cool it looks driving down the street, and how long it will last before failure, etc, then maybe your car _is_ better than the civic. But that's also a different question.

You're trying to obfuscate this issue by arbitrarily calling something cheating, but you've never been able to logically draw the line between cheating (applying a transfer function with an external box) and not cheating (Carver applying a transfer function within the amplifier). You also haven't been able to reconcile this arbitrary rule set of yours with modifications like output zobels affecting frequency response (is that internal or external?). You didn't want to answer that question. I know why. Your entire argument is an arbitrary construct, and that kind of **** is hard as hell to defend.



> _Now_, I am done with you.


----------



## feeshta

MarkZ said:


> I get what you're saying, but could you explain the nonlinearity you're talking about? Most amplifiers tend to exhibit _lower_ distortion as output rises, not higher (at least until you begin to approach clipping). The speaker is also going to be less reactive at higher output levels due to power compression (the ratio of reactive to resistive gets lower). Yes, motional EMF increases with cone motion, but so does output voltage (actually, at a somewhat lower rate of increase than output voltage, due again to power compression). So it's not clear to me how the differences in most amps will appear more prominent at higher levels.


I'm not talking about non-linearity, I'm talking about distortion. The inability to make a loudspeaker accurately reproduce a given signal at high listening volumes. The key here is that most testing is done using a non-reactive load, so as to accurately meassure the amplifier's output without any interference. But in the real world, the amp has to deal with a lot of interference.

I'm not an electrical engineer, but I work with some guys who are class A engineering eggheads, they types who design weaponry for the military, and this is how they explained it to me. A loadspeaker is a reactive load. It doesn't simply accept a signal and turn it into sound. The speaker has a reaction to the input of signal, and essentially feeds back into the amplifier. The greater the input signal, the greater the feedback. Some amplifiers are better able to absorb this feedback and still force the speaker to do the correct thing than others, and raw wattage is not an accurate meassure of the amps ability to do so. 

It's similar to the seperate measures for torque and horsepower when measuring the performance of an automotive engine, but there is no uniformly agreed upon standard of measuring this ability that I am aware of. Wattage measures the ability to do work over time, but it does not accurately measure the effective "brute strength" of the amplifier in any given instant. Damping factor is one measure that they believed does reflect a somewhat accurate measurement, but they said it is flawed as a measurement in some way I can't remember off the top of my head. One thing I do know, the amp I have been so impressed with, has a damping factor that is through the roof compared to most at >900. 

In the listening experience, the best way to describe the difference is like this. With a substandard amplifier, when you listen at high volume the sound starts to just all blend together. You get this sense of just "noise" behind everything, particularly with recordings that are heavy on guitar and have multiple parts. With a really good amp, you can still clearly hear all of the individual parts that make up the whole of the sound, and that sense of noise in the background dissappears. I always thought that it was just down to your ears being overwhelmed and becoming incapable of seperating out all of the different sounds at high volume. I found out that this is not the case, it was just that the amp couldn't make the loudspeaker accurately reproduce such complexity at high volumes.


----------



## MarkZ

feeshta said:


> I'm not talking about non-linearity, I'm talking about distortion. The inability to make a loudspeaker accurately reproduce a given signal at high listening volumes. The key here is that most testing is done using a non-reactive load, so as to accurately meassure the amplifier's output without any interference. But in the real world, the amp has to deal with a lot of interference.
> 
> I'm not an electrical engineer, but I work with some guys who are class A engineering eggheads, they types who design weaponry for the military, and this is how they explained it to me. A loadspeaker is a reactive load. It doesn't simply accept a signal and turn it into sound. The speaker has a reaction to the input of signal, and essentially feeds back into the amplifier. The greater the input signal, the greater the feedback. Some amplifiers are better able to absorb this feedback and still force the speaker to do the correct thing than others, and raw wattage is not an accurate meassure of the amps ability to do so.
> 
> It's similar to the seperate measures for torque and horsepower when measuring the performance of an automotive engine, but there is no uniformly agreed upon standard of measuring this ability that I am aware of. Wattage measures the ability to do work over time, but it does not accurately measure the effective "brute strength" of the amplifier in any given instant. Damping factor is one measure that they believed does reflect a somewhat accurate measurement, but they said it is flawed as a measurement in some way I can't remember off the top of my head. One thing I do know, the amp I have been so impressed with, has a damping factor that is through the roof compared to most at >900.


Yeah, I understood that from your last post. Testing into a reactive load is important, I agree with you. It's also fairly easy to do this, and many people DO in fact use this strategy in their measurements. You're also right that the motional EMF "feedback" is going to exacerbate these issues. However, modern designs all have a very large damping factor, enough to mitigate these problems (once the output impedance becomes much less than the load resistance, which is almost universally the case...). So I'm not convinced that this is where we need to look to find these differences.



> In the listening experience, the best way to describe the difference is like this. With a substandard amplifier, when you listen at high volume the sound starts to just all blend together. You get this sense of just "noise" behind everything, particularly with recordings that are heavy on guitar and have multiple parts. With a really good amp, you can still clearly hear all of the individual parts that make up the whole of the sound, and that sense of noise in the background dissappears. I always thought that it was just down to your ears being overwhelmed and becoming incapable of seperating out all of the different sounds at high volume. I found out that this is not the case, it was just that the amp couldn't make the loudspeaker accurately reproduce such complexity at high volumes.


It's also still not clear to me why these effects ("feedback" & reactive loads) would become more prominent with output level. That's the missing link here, I think.

I've had the same observations as you, but I've always attributed that to clipping. Which occurs earlier than most people think.


----------



## Hanatsu

MarkZ said:


> but I've always attributed that to clipping. Which occurs earlier than most people think.


Heard that as well. Is there any drawbacks with soft-clip circuits like NAD used to incorporate in their amps?


----------



## subwoofery

Hanatsu said:


> Heard that as well. Is there any drawbacks with soft-clip circuits like NAD used to incorporate in their amps?


It would only be more pleasing to the ear - drawbacks? I'd say headroom... maybe...

Kelvin


----------



## MarkZ

I don't know what NAD does. If it's just a limiter, like what I understand McIntosh's soft clip feature in their amps to be, there is no drawback. Unless you count not being able to have a specific amp's clipping "signature" present anymore. Soft clip would SUCK for guitar players, and for "audiophiles".


----------



## RNBRAD

McIntosh uses what they call "power guard" feature which is an input attenuator. When it sees distortion rating beyond a certain ?% as compared to input vs output signal it maintains it at that preset level. I've ran mine into power guard activition, it is lightening fast and totally inaudible or lets say I have never discerned any audible drawbacks. If it didn't activate a light when it turns on, I would have no idea it's on. However for those that want to run their amps into clipping for SPL purposes or whatever, they offer a nifty inactivation switch.


----------



## MarkZ

Which sounds like a well-calibrated limiter to me.  Used in pro audio all the time, except for a different reason mostly.


----------



## feeshta

Well, the US Amps I was referring to have absolutely zero internal processing. No built in cross-over, no bass boost, nothing except a gain control. They don't have a "sound" to them, other than powerful.


----------



## feeshta

MarkZ said:


> Yeah, I understood that from your last post. Testing into a reactive load is important, I agree with you. It's also fairly easy to do this, and many people DO in fact use this strategy in their measurements. You're also right that the motional EMF "feedback" is going to exacerbate these issues. However, modern designs all have a very large damping factor, enough to mitigate these problems (once the output impedance becomes much less than the load resistance, which is almost universally the case...). So I'm not convinced that this is where we need to look to find these differences.
> 
> 
> 
> It's also still not clear to me why these effects ("feedback" & reactive loads) would become more prominent with output level. That's the missing link here, I think.
> 
> I've had the same observations as you, but I've always attributed that to clipping. Which occurs earlier than most people think.


As others here have noted, the McIntosh amp being replaced when I did my swap had the "power guard" feature, which eliminates clipping by instantaniously cutting input gains when the output would end up as distortion. So it was not the amplifier clipping that caused that vague sense of noise. I knew that at the time, which is probably why I attributed it to hearing overload rather than actual distortion from the amplifier. 

I think what I was actually hearing was distortion introduced between the amplifier's outputs and the speaker's actual end output though. the fact that this distortion dissappeared when I swapped amps leads me to believe the new amp, the US Amps, was able to more cleanly drive the loudspeakers, even within the range of clipping. 

It is possible that the power-guard feature limits some transients, but the sense of noise was present prior to the point where the powerguard light would activate. Really I only ever saw that light activate when I was running subwoofers with it, but it is possible it could mellow out peaks in the musical signal, depending how it was engineered. I didn't really hear an audible difference when I switched it off though. 

One notable difference between the US Amps TU series and almost all other amplifiers is that is has no AGC(automatic gain control). This one feature may also be a key to the difference in sound. An AGC is normally there to prevent the amp from toasting itself, but the tube hybrid design doesn't need it. It may simply not temper the transients present in music as much.


----------



## MarkZ

That's exactly what power guard does. It limits transients. It does it "cleanly" as opposed to harshly, but it's still modifying the signal. That's what limiters do. They're also called compressors, so it's not far-fetched that it could have been compressing the dynamics.  It's just being triggered by something different from what normal limiter/compressors are triggered with.

It's a very nice circuit, IMO. More amps should include them. You could install your own limiter on any amp and it would do the same thing, but you'd have to "tune" it to work with that particular amp.


----------



## feeshta

MarkZ said:


> That's exactly what power guard does. It limits transients. It does it "cleanly" as opposed to harshly, but it's still modifying the signal. That's what limiters do. They're also called compressors, so it's not far-fetched that it could have been compressing the dynamics.  It's just being triggered by something different from what normal limiter/compressors are triggered with.
> 
> It's a very nice circuit, IMO. More amps should include them. You could install your own limiter on any amp and it would do the same thing, but you'd have to "tune" it to work with that particular amp.


I don't know why you would want to. If it's not clear, the US Amps without any processing sounds much better than the McIntosh did with it. That's not just my opinion either. Everyone who heard the car before and after agreed.


----------



## RNBRAD

It adjusts the input level a 1000x a second, that's all it does and only does this when your reach a preset distortion level. Like I said, it is inaudible. If your hearing something between amps, this is not it. The USAmps is going to run into clipping with audible distortion. The Mcintosh won't allow itself past that level due to the scenario given in the 1st sentence.

Let me put it this way. The McIntosh will sound exactly the same at 10 watts as it will with the PG light pegged "on". Not sure where your distortion was coming from but my money it wasn't the Mac amps.


----------



## MarkZ

Right, but if the US Amps amplifier _isn't_ reaching clipping, while the McIntosh _is_ (but the clipping is being "softened" by power guard), then the McIntosh will sound more "compressed" than the US Amps one. 

It's not that the McIntosh circuit is inaudible -- it's that it trades distortion for compression. This is a pretty good strategy, IMO (although I'd probably prefer to have some control over attack/decay...). But it's still inferior to not clipping at all.


----------



## feeshta

MarkZ said:


> Right, but if the US Amps amplifier _isn't_ reaching clipping, while the McIntosh _is_ (but the clipping is being "softened" by power guard), then the McIntosh will sound more "compressed" than the US Amps one.
> 
> It's not that the McIntosh circuit is inaudible -- it's that it trades distortion for compression. This is a pretty good strategy, IMO (although I'd probably prefer to have some control over attack/decay...). But it's still inferior to not clipping at all.


Personally I don't think the powerguard itself is the main difference, since switching powerguard off didn't result in any audible difference. I think it's more likely the lack of an AGC circuit. This might allow the US Amps to output signifigantly more power for a matter of instants than a normal solid state amplifier is capable of, thereby lending greater power on a momentary basis, but not reflected in the RMS output specs.


----------



## RNBRAD

Well you have to realize the compression and expansion of the signal is 1000x a second. It is so fast It "is" inaudible, reviewers will tell you that, McIntosh will tell you that, I will tell you that. Totally in audible, never have the slightest clue if and when or if it has ever engaged. 

Now having an inactive agc or even an active "PG" agc circuit causing transient or headroom issues throughout the power range. Never heard nore experienced.


----------



## MarkZ

Of course it's audible. There's no free lunch. You try to get 200w out of a 100w McIntosh amp, powerguard will prevent it from clipping, making it sound better* than a normal 100w amp under the same conditions, but it cannot prevent the dynamics compression that accompanies these circuits. The 200w amp will still sound better.

* = "better" here is not necessarily the case, but it probably is most of the time for most people ... under some circumstances (e.g. very short duration peaks), it may actually sound better to clip. This is why it's so important to have a knowledgeable and experienced person adjusting your limiter than to just throw one into your system and hope that the defaults are good. Or, alternatively, to have a reputable company like McIntosh controlling the attack and release times, and developing whatever other smart dynamic algorithms that might be included in "power guard" to reduce the audibility of artifacts.


----------



## MarkZ

Of course it's audible. There's no free lunch. You try to get 200w out of a 100w McIntosh amp, powerguard will prevent it from clipping, making it sound better* than a normal 100w amp under the same conditions, but it cannot prevent the dynamics compression that accompanies these circuits. The 200w amp will still sound better.

* = "better" here is not necessarily the case, but it probably is most of the time for most people ... under some circumstances (e.g. very short duration peaks), it may actually sound better to clip. This is why it's so important to have a knowledgeable and experienced person adjusting your limiter than to just throw one into your system and hope that the defaults are good. Or, alternatively, to have a reputable company like McIntosh controlling the attack and release times, and developing whatever other smart dynamic algorithms that might be included in "power guard" to reduce the audibility of artifacts.


----------



## RNBRAD

Mark then you need to argue with McIntosh about how audible their circuit is. It's volume limited, meaning you can't push this amp beyond certain performance capabilities. Just that simple. You get a 100 watts or whatever and that's it. You can adjust all the gains you want input/output raise your source units volume...guess what? Nothing... the amp does nothing. It doesn't run into clipping, you can't hear compression, nothing. You can't tell your out of pwoer, nothing. That's why it's inaudible cause you can't push this amp beyond it's limits as to where it's output changes. it just stops making power. The PG acg does a great job of controlling the input as to control the output stage. It doesn't run the output into a brick wall where it comrpesses to the point it's audible. Go test one and get back with me. 

Now if you want to compare how a 200 watt xxx amps sounds compared to a 100 watt Mcintosh on xxy speakers, that's another thread all together. Not even close to the discussioin here.

Cajunner, very well stated. I've said many times people perceive "distortion" as sounding better, no question!!


----------



## RNBRAD

Maybe this will help shed some light. 

McIntosh Laboratory Part 2


----------



## MarkZ

RNBRAD said:


> Mark then you need to argue with McIntosh about how audible their circuit is. It's volume limited, meaning you can't push this amp beyond certain performance capabilities. Just that simple. You get a 100 watts or whatever and that's it. You can adjust all the gains you want input/output raise your source units volume...guess what? Nothing... the amp does nothing. It doesn't run into clipping, you can't hear compression, nothing. You can't tell your out of pwoer, nothing. That's why it's inaudible cause you can't push this amp beyond it's limits as to where it's output changes. it just stops making power. The PG acg does a great job of controlling the input as to control the output stage. It doesn't run the output into a brick wall where it comrpesses to the point it's audible. Go test one and get back with me.
> 
> Now if you want to compare how a 200 watt xxx amps sounds compared to a 100 watt Mcintosh on xxy speakers, that's another thread all together. Not even close to the discussioin here.


But what you're talking about is physically impossible. If you have a signal that's higher than a 100w amp could faithfully reproduce, and you MODIFY that signal so that it remains linear (which is what a limiter does), then it's going to produce an audible difference from what another amp would produce. The reason a 200w amp is relevant here is because I'm pointing out that power guard is not a replacement for higher output capabilities. You're saying it's like a governor... which is a fine analogy, but the dynamics of music mean that governor compresses.

Is this the same "powerguard"?

McIntosh Laboratory Part 2

If so, it's a *compressor*.

Here's an exerpt:

"_This was the basis of the Power Guard circuit used in the first Power Guard equipped amplifier, the MC2205. However, later versions became much more sophisticated and sensed not only voltage but also current which was a measure of the power actually delivered to the speaker. Power guard is now described as a waveform comparison circuit that continuously monitors the output signal and compares it with the input signal. If distortion occurs at the output, the Power Guard circuit reduces the input signal level until the distortion is reduced below clipping. The amplifier gain is then restored. 

The whole process of the Power Guard circuits takes only a fraction of a second. Although this action is not audible, the resulting sound at maximum power levels always stays "clean"._"

That's a limiter, dude. 

Where you're getting this "inaudible" stuff, I think, is from the claims from the manufacturer that the limiter function does not insert audible artifacts. That's what everybody strives for when they use a limiter. That _doesn't _mean there's no audible difference between using a limiter and having unlimited power on tap. What it means is that artifacts that are notorious for being introduced when using a limiter the wrong way (e.g. pumping) are not present because they implemented it well.


----------



## MarkZ

RNBRAD said:


> Maybe this will help shed some light.
> 
> McIntosh Laboratory Part 2


Hahaha I just noticed we linked the same thing...


----------



## subwoofery

MarkZ said:


> But what you're talking about is physically impossible. If you have a signal that's higher than a 100w amp could faithfully reproduce, and you MODIFY that signal so that it remains linear (which is what a limiter does), then it's going to produce an audible difference from what another amp would produce. The reason a 200w amp is relevant here is because I'm pointing out that power guard is not a replacement for higher output capabilities. You're saying it's like a governor... which is a fine analogy, but the dynamics of music mean that governor compresses.
> 
> Is this the same "powerguard"?
> 
> McIntosh Laboratory Part 2
> 
> If so, it's a *compressor*.
> 
> Here's an exerpt:
> 
> "_This was the basis of the Power Guard circuit used in the first Power Guard equipped amplifier, the MC2205. However, later versions became much more sophisticated and sensed not only voltage but also current which was a measure of the power actually delivered to the speaker. Power guard is now described as a waveform comparison circuit that continuously monitors the output signal and compares it with the input signal. If distortion occurs at the output, the Power Guard circuit reduces the input signal level until the distortion is reduced below clipping. The amplifier gain is then restored.
> 
> The whole process of the Power Guard circuits takes only a fraction of a second. Although this action is not audible, the resulting sound at maximum power levels always stays "clean"._"
> 
> That's a limiter, dude.
> 
> Where you're getting this "inaudible" stuff, I think, is from the claims from the manufacturer that the limiter function does not insert audible artifacts. That's what everybody strives for when they use a limiter. That _doesn't _mean there's no audible difference between using a limiter and having unlimited power on tap. What it means is that artifacts that are notorious for being introduced when using a limiter the wrong way (e.g. pumping) are not present because they implemented it well.


Have to agree with MarkZ here... The audible difference you're (_*feeshta*_) hearing is the power guard limiting max output to keep the output signal clean VS a more powerful amplifier that would keep on going, level wise, and still be clean up to its max RMS... 
That would be the main difference between the McIntosh and the US Amps you had...

Kelvin


----------



## putergod

subwoofery said:


> That would be the main difference between the McIntosh and the US Amps you had...


Not to mention that, in my experience, US Amps was notorious for severely underrating their amps. All of the ones I had, prior to the "sell out", put out almost double what they were rated at (tested with an O-Scope - so this is before clipping).

McIntosh "may" do the same, but I've never had one, so I've never measured one.


----------



## RNBRAD

Mark I've used McIntosh amplifiers since 1994, that is 18yrs!! I competed with Mcintosh for 8 of those years. I can set you in my vehicle, turn the volume until the Power Guard light is flashing like a christmas tree on roids. ( I can actually view them in real time unlike most). You may not believe it because I can tell you have little to no experience with these amps, and that's ok, but you can never tell when the PG is activated. I can back off the volume as to where the PG is inactivated. In no way shape form or fashion could you tell it was in PG mode. I never said it wasn't a limmiter or a compressor, it is. The thing is Mark you lump it in with all other limiters and compressors in the market (your proverbial box). I think you need to "experience" it and then we can discuss it a little futher. We can read and discuss it all we want, but to fully understand what I'm talking about, need to spend some time in the laboratory listening. 

My guess it's not the same version of PG. I'm assuming it's been improved over the years with better circuitry as technology allows. It does haved it's own patent, so probably not many like it. *So I wouldn't try to put it in the proverbial box and then assume it's performance parameters based on your insight or readings or whatever you base it on as comparing it with other limiters or other acg's*.


----------



## RNBRAD

subwoofery said:


> Have to agree with MarkZ here... The audible difference you're (_*feeshta*_) hearing is the power guard limiting max output to keep the output signal clean VS a more powerful amplifier that would keep on going, level wise, and still be clean up to its max RMS...
> That would be the main difference between the McIntosh and the US Amps you had...
> 
> Kelvin


What explains the difference he experienced with it being off? He said he couldn't tell a difference with it on or off. We going to assume it's limiting output anyway? 

I can't tell a difference with it on or off either except for full volume bass passages with it off I can get may 2 to 3 db more output but just audible. My upper end range amp, no way!!


----------



## MarkZ

RNBRAD said:


> Mark I've used McIntosh amplifiers since 1994, that is 18yrs!! I competed with Mcintosh for 8 of those years. I can set you in my vehicle, turn the volume until the Power Guard light is flashing like a christmas tree on roids. ( I can actually view them in real time unlike most). You may not believe it because I can tell you have little to no experience with these amps, and that's ok, but you can never tell when the PG is activated. I can back off the volume as to where the PG is inactivated. In no way shape form or fashion could you tell it was in PG mode. I never said it wasn't a limmiter or a compressor, it is. The thing is Mark you lump it in with all other limiters and compressors in the market (your proverbial box). I think you need to "experience" it and then we can discuss it a little futher.


I think I'll tell you the same thing I told you in the other thread. You're not the only one with experience. I understand how limiters work (I've *designed* them myself). McIntosh's comparator implementation is excellent, but it's also a pretty common approach. It's so common that wikipedia even has an example of it. Their patent is based on a slight variation of the theme - including a clever way of identifying clipping - like most patents are. It's also an in-the-box solution, which has a ton of advantages.

But the key is that the mechanism of operation is the same. It (according to the link that you provided) adjusts the gain to prevent distortion. Adjusting the gain is audible. I'm sure it does it seamlessly, which is great (and what every experienced tech tries to do), but that doesn't mean it can achieve the impossible.


----------



## MarkZ

cajunner said:


> Peavey has a distortion circuit, DDL, I think..
> 
> Crown has one too, right?
> 
> Blaupunkt uses THD>L,
> 
> McIntosh has Power Guard
> 
> Yamaha has a servo circuit
> 
> NAD/Proton had a 2-rail power supply that increased peaks
> 
> Velodyne was full servo
> 
> what we really need is a thread on amplifier distortion circuits, a comparison/shootout kind of thing... then people could reference it when trying to believe one manufacturer's advertising copy over another's....


Servo is something else completely.

What most people don't realize is that the vast majority of car amps already have a comparator circuit that corrects for distortion in the output by modifying the input signal. That's right, _majority_. This is fairly easily accomplished by simply tying the output directly to one input of the differential circuit in the input stage. There are two problems with this approach though ("audiophiles" will tell you there are more than that... ). One is stability at high frequencies, as with any high gain feedback network. But there are tricks around that. The second is that it doesn't really work near clipping, because the circuit is too "dumb" to realize that clipping is responsible for the distortion, and so it doesn't know that the right answer is to reduce the gain. You can make this circuit "smart" by instructing it to reduce overall gain in the presence of signs that distortion is exceeding some predefined threshold. I don't know exactly what McIntosh uses for detecting these signs, but that's what they've patented, not the mechanism of action. Other companies probably have their own. But there's not much you can do about the mechanism of action because it's a _causal_ system. The only thing you can really do is adjust the attack and release, and if you can do this dynamically to further reduce artifacts, then you're ahead of the curve... and have something else to patent.


----------



## RNBRAD

MarkZ said:


> I think I'll tell you the same thing I told you in the other thread. You're not the only one with experience. I understand how limiters work (I've *designed* them myself). McIntosh's comparator implementation is excellent, but it's also a pretty common approach. It's so common that wikipedia even has an example of it. Their patent is based on a slight variation of the theme - including a clever way of identifying clipping - like most patents are. It's also an in-the-box solution, which has a ton of advantages.
> 
> But the key is that the mechanism of operation is the same. It (according to the link that you provided) adjusts the gain to prevent distortion. Adjusting the gain is audible. I'm sure it does it seamlessly, which is great (and what every experienced tech tries to do), but that doesn't mean it can achieve the impossible.


So it does it seamlessly but audible according to you? Since it is audible, then surely you could dinstinguish when the circuit is activated without a problem right? Can you put your money where your mouth is, perhaps a little wager? Would you like to go to your local Mcintosh dealer and see if you can identify the PG when activated? How far you willing to go to prove your point? or disprove my experience, or Mcintosh's advertised claims, or countless reviews of the PG circuitry as operating undetected? Lets do this, I'll set it up, just tell me what town you live in. Mcintosh reps/dealers live for these opportunities.

We can surely find a 3rd party DIYMA member as an escro mediator.


----------



## MarkZ

Oh brother.


----------



## RNBRAD

Seriously!!! Take a trip, pay a visit. I'll paypal your trip fee's, whatever, then you can report back your experience here. Talk is just that.


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## MarkZ

Ok, only if you contact Richard Clark and do his challenge.


----------



## RNBRAD

Here's a direct quote from McIntosh. Surely if someone can prove them wrong we can sue for false advertisement. They even said absolutely. I wonder how sure they are? Mark you tell them what you told me!! Make them understand.



> When the differ-
> 
> ence exceeds 0.3% the Power
> 
> Guard activates the PG light
> 
> and a dynamic electronic at-
> 
> tenuator at the amplifier input
> 
> reduces the input volume just
> 
> enough to prevent any further
> 
> increase in distortion. The
> 
> Power Guard circuit acts so
> 
> fast that there are absolutely
> 
> no audible side effects and
> 
> the sonic purity of the music
> 
> reproduction is perfectly
> 
> preserved.


----------



## MarkZ

RNBRAD said:


> Here's a direct quote from McIntosh. Surely if someone can prove them wrong we can sue for false advertisement. They even said absolutely. I wonder how sure they are? Mark you tell them what you told me!! Make them understand.


"No audible *side effects*."

As I explained earlier, side effects (I used the word "artifacts"...same thing) have always been a problem with limiters. That's why it usually requires that the user is skilled to "tune" the limiter correctly to make pumping inaudible. McIntosh guarantees that they've done this. I believe them.

That doesn't mean limiting is inaudible. It's the defacto standard for dynamic compression.

Edit: I just found the patent. Nothing particularly groundbreaking there. They're just building a compressor _into_ the amp. Which, as I mentioned, is very useful for the reasons I stated. But it's still just a compressor.


----------



## RNBRAD

Im only refering to limiting is inuadible in regards to the PG circuitry. I don't doubt that it is audible in most cases. Those cases weren't part of our discussion though. 

Stay focused here, were only talking as to whether this particular device is audible. That is the PG made and patented by Mcintosh. Don't chase rabbits.


----------



## MarkZ

Then first explain how this device ISN'T a traditional limiter. Because the McIntosh marketing department came up with a fancy name? The schematics are on the site I linked. Compare it to the limiter wikipedia page.


----------



## RNBRAD

Mark, with all seriousness, this is where you run into problems with your theory. Your idea's are based on likelihood versus reality and you'll argue against reality based on this perception. You can't look at this freaking patent and accurately predict it's audible performance. I told you how it performs based on 18yrs experience with said product. I showed you Mcintosh's claims of it's performance. I offered you a deal to listen to them in person to experience it for yourself. I mean what more do you want?????? I think if God himself appeared to you, you would still say " but look God, this similiar design does this so this design can't possibly exhibit said parameters because of this algorithym of said inductance variation of the atom of the nucleas of the molecule when combined under 30 degrees celsius for 30 minutes produces comb filtering of the isotopes of pure copper inducts noise into the PG causing audible compression." lol.


----------



## Jesus Christ

RNBRAD said:


> I think if God himself appeared to you...


I asked god, he says Mark is right.


----------



## RNBRAD

Jesus Christ said:


> I asked god, he says Mark is right.


OMG I mean Jesus, that's hillarious!! :laugh::laugh:


----------



## thehatedguy

Still waiting on a blameless car amp to come to market.


----------



## squeak9798

cajunner said:


> Lycan wiped the floor with me on this topic about 3 years ago, but without his clarity on this it's going to be contentious.
> 
> Something about linear analysis, four different parameters, anything outside of FR, Distortion, Noise, and gain, and there was nothing that couldn't be explained by changes in these parameters.
> 
> My thing about Richard Clark's challenge, is that he gets to change the (chosen) amp's output to sound like another amp's output, until it's sonically indistinguishable.
> 
> Now, it costs a ton in processing to get there, with circuits you can't buy on ebay.
> 
> So, if you wanted him to "mimic" the sound of a particular amp, he controls the parameters so that you never hear the amp at clipping, you won't hear the "noise" or the rise in distortion from reaching the circuit's limitations, it's pretty much a confidence scam in reverse, because once you change enough parameters of an amplifier's circuit, you don't have the circuit! It's not the same amplifier, he doesn't just level gains and measure power and stay inside the distortion envelope, he messes with FR too!


He used basic equalization only when one amplifier's FR was outside of stated tolerance, and the listener was able to choose which amplifier received the equalization.

How many people use EQ in their systems? You are adjusting the FR of the amplifier in your own system with the addition of equalization, so why is it completely unreasonable for RC to do the same? Why is EQ in your car or house different than RC using it in his challenge? The end result is exactly the same.....manipulation of the amplifier's frequency response. 

RC's challenge wasn't designed to prove all amps sound the same, it was designed to prove when amps won't sound different. It does that successfully, and isn't a scam when you understand the point of the challenge.


----------



## MarkZ

RNBRAD said:


> Mark, with all seriousness, this is where you run into problems with your theory. Your idea's are based on likelihood versus reality and you'll argue against reality based on this perception.


Your relentless "you have no experience" accusations are really tiresome to read. You know nothing about me.


----------



## MarkZ

cajunner said:


> I believe McIntosh when they say their circuit is the best-case implementation of distortion reduction in practice, and without labeling their circuit as limiting; to group it in with all other limiters is disingenuous.


But it _is_ a limiter. The schematic is right there. Go look at it!

Have they elaborated on it since then? Maybe. But you're just guessing that it does something entirely different. There's zero evidence of that. Certainly not from their own marketing department, whose explanation directly mirrors the one in the patent.

Come on guys. Now you're really delving into the depths of magic here. "They say it does XYZ, we have a schematic that shows XYZ, but they also say it sounds wicked good, so it _must_ be doing something mysterious and groundbreaking and something that defies the whole concept of causality!"



> If Peavey's DDL circuit (patented, too) may be better or it may be worse,


Or the same.  Also a limiter.



> I would assume that whoever came up with it is being compensated for their licensed use of it, where McIntosh has the distinction of developing Power Guard in-house, which could actually be a hindrance in proving what works best, as they may not wish to implement it's license in Chinese buildhouses, or they want to keep a certain mystique unique to their own marketing ploys, or whatever.


There _is_ no mystique in discrete electronics.


----------



## RNBRAD

MarkZ said:


> Your relentless "you have no experience" accusations are really tiresome to read. You know nothing about me.


I know one thing very very well Mark, you'll argue with a fence post while trying to convince a fence post it's a picket even when you know it's a fence post.


----------



## MarkZ

Don't be so narcissistic. I've been saying the same thing about powerguard long before you showed up.


----------



## RNBRAD

Mark, you ever listened to a Mcintosh amp? You been saying PG is audible?

I bet I was using "power guard" before you were out of diapers.


----------



## co_leonard

In my (limited) experience, amp SQ does change over the years and even different generations of the same amplifier tend to have minor sound quality differences.

I know someone with two DLS Ultimate A3 amplifiers. One was purchased back in 2005 and stored away. The other was purchased just recently. Both went in his car a couple of weeks ago, in a temporary build just to get the system sounding.

After both amps had around a month of constant use (he listens around 5 hours a day during his trips), he and I had a serious listen. One amp was driving both tweeters and the other was driving both midbasses in full-active. We swapped the amps to hear if they had a characteristic "sound." The older amp sounded warmer and fuller but less detailed on the top-end. The newer amp sounded brighter and livelier but thinner. 

Perhaps the capacitors of the old amp had changed values during its 7-year storage period? That's what we figured would account for the difference in sound quality. 

And perhaps over time, the sound of the newer amp will slowly become warmer and fuller as well? Guess we'll have to wait and hear..


----------



## Hanatsu

co_leonard said:


> In my (limited) experience, amp SQ does change over the years and even different generations of the same amplifier tend to have minor sound quality differences.
> 
> I know someone with two DLS Ultimate A3 amplifiers. One was purchased back in 2005 and stored away. The other was purchased just recently. Both went in his car a couple of weeks ago, in a temporary build just to get the system sounding.
> 
> After both amps had around a month of constant use (he listens around 5 hours a day during his trips), he and I had a serious listen. One amp was driving both tweeters and the other was driving both midbasses in full-active. We swapped the amps to hear if they had a characteristic "sound." The older amp sounded warmer and fuller but less detailed on the top-end. The newer amp sounded brighter and livelier but thinner.
> 
> Perhaps the capacitors of the old amp had changed values during its 7-year storage period? That's what we figured would account for the difference in sound quality.
> 
> And perhaps over time, the sound of the newer amp will slowly become warmer and fuller as well? Guess we'll have to wait and hear..


DLS improves the circuits in their amps once in a while but keeps the chassis, therefore many think it's the same amps now as they were 5 years back. 

Chanses are they did improve/change something in the newer amp.

Sent from my Samsung Galaxy 3 via Tapatalk.


----------



## subwoofery

RNBRAD said:


> What explains the difference he experienced with it being off? He said he couldn't tell a difference with it on or off. We going to assume it's limiting output anyway?
> 
> I can't tell a difference with it on or off either except for full volume bass passages with it off I can get may 2 to 3 db more output but just audible. My upper end range amp, no way!!


Not sure how audible the PG would be when switching on and off - my friend has a McIntosh amp and it surely does its job well... 
Compare it to another amp of the same rating as the McIntosh and drive it through the edge of distortion - there will be some audible differences with the McIntosh obviously sounding better 
Compare it to another amp that can output double what the McIntosh does, the differences would be clearly audible but the more powerful amp will sound better... 

I do think that the McIntosh amp is limiting its headroom since it lowers the input gain whenever it can't output signal without sending more than 0.3% distortion with it

Kelvin


----------



## OSN

RNBRAD said:


> Mark, you ever listened to a Mcintosh amp? You been saying PG is audible?
> 
> I bet I was using "power guard" before you were out of diapers.


18 years...diapers...yeah, you really don't know anything about MarkZ. He's closer to wearing them again than getting out of them. :laugh:


----------



## RNBRAD

subwoofery said:


> Not sure how audible the PG would be when switching on and off - my friend has a McIntosh amp and it surely does its job well...
> Compare it to another amp of the same rating as the McIntosh and drive it through the edge of distortion - there will be some audible differences with the McIntosh obviously sounding better
> Compare it to another amp that can output double what the McIntosh does, the differences would be clearly audible but the more powerful amp will sound better...
> 
> I do think that the McIntosh amp is limiting its headroom since it lowers the input gain whenever it can't output signal without sending more than 0.3% distortion with it
> 
> Kelvin


It won't sound better it will sound louder. If I limit every Mcintosh amplifier to never put out more than 0.3% distortion, then how can one sound "better" than another? I can tell when people have limited experience with Mcintosh amps. You guys don't understand it so lets put it in this box with the other amplifiers to help understanding. Wrong idea!!! You can't drive a Mcintosh to distortion with PG activiated, it's impossible. You can take a 100 watt Mcintosh and put it up against a 1000 watt Mcintosh. The difference between the 2 will be volume output only. Let me try an analogy here to help those to understand how a Mcintosh functions with the power guard and for those that didn't fully read the link above. 

Ok, I have a relatively high-end home system but... at a certain volume I start getting distortion. That volume is numbered -100db all the way to -1. When I reach about a 2pm position on the dial which reads about -16db, this is where I can audibly here distortion every time. I usually never go past-24 as this is past the comfortable volume range and it's starts causing pain. Now If I listen to this system at -24 is it maxed out? Well no!!! Do I hear any distortion? Well no!!! I said I don't hear it till -16db. Ok now lets take this amp and were are going to control this thing so it will never perform beyond this volume level of -24db. It still has all the headroom performance you can ask from it. It's ultra clean but once you reach -24db, the dial turns no more, no more volume can be had. That's it!!! That's a Mcintosh with PG, that's how it performs!!!Is that good? Is that bad? You decide. No matter how hard you try, with all the Mcintosh's in the world, once they reach -16db on the dial, they are done. The orange PG light is blinking like a christmas tree on roids, but audibly you have no clue. The difference between Mcintosh to Mcintosh is volume based related to power output. Does it limit the input gain? I would say it stops it, not just limits it. It stops and controls it at a point as to where there is not audible change from 1 watt to max power other than volume. That's mcintosh's claim to fame. They also rate their amps differently than anyone else. They rate their amps at worst possible scenario. Their distortion ratings are the "highest" point from 0 to rated output. Most amps rate theres where it is best which is generally right before clipping. That's another Mcintosh claim to fame, their amps will never exceed rated specifications from 0 to rated power output. So worst possible scenario distortion rating from 0 to rated power is always better than .005%. How good are these amps? Better than most people realize!!

You want a Mcintosh to run into audible clipping and distortion like other amplifiers, no problem, then turn the Power Guard off and let it rip!! But for someone to say the PG is audible based on similiar limiter designs of other amps is absolutely obsurd and they have little to no experience with a McIntosh!!!


----------



## AAAAAAA

RNBRAD said:


> Here's a direct quote from McIntosh. Surely if someone can prove them wrong we can sue for false advertisement. They even said absolutely. I wonder how sure they are? Mark you tell them what you told me!! Make them understand.


*…

reduces the input volume …*


I think you just proved Mark’s point. If you don’t count "reduces volume" as something audible then there is no use arguing with you. 
Of course it would have to be reduced by a significant amount for one to be able to hear. It would be safe to say that it can only be heard once it limits over a certain amount.


----------



## RNBRAD

AAAAAAA said:


> *…
> 
> reduces the input volume …*
> 
> 
> I think you just proved Mark’s point. If you don’t count "reduces volume" as something audible then there is no use arguing with you.
> Of course it would have to be reduced by a significant amount for one to be able to hear. It would be safe to say that it can only be heard once it limits over a certain amount.


You can't hear it, anything period, if it reduces volume you can't tell, you can't hear it. If it compresses the signal you can't hear it!! Read my analogy above. Some reason you guys don't understand you can't hear it. The volume is just done. It doesn't drop once you get to that point, there is just no more. Read my analogy above. Did I mention you can't hear it?


----------



## RNBRAD

It doesn't reach a point then decreases the volume to then compensate. It never reaches that point to begin with, so then there is no audible compensation. This make sense at all?


----------



## AAAAAAA

I see the point I guess. It's like walking in a room and some guy that is usually standing is sitting. You leave the room knowing the guy was sitting. There is no way to know that usually he is standing. 

Same thing with the music compression, while listening how are you to know a certain part of the track should be somewhat louder than what you heard.... mmmmmm


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## MarkZ

RNBRAD said:


> It won't sound better it will sound louder. If I limit every Mcintosh amplifier to never put out more than 0.3% distortion, then how can one sound "better" than another? I can tell when people have limited experience with Mcintosh amps.


Again with this?

_I_ can tell when people have limited experience with compressor/expanders. It's well-established what the audible effects of a compressor are, as every pro audio guy in the history of the planet has used one. I already provided this link, which covers them in great detail, but you didn't read it. 

Dynamic range compression - Wikipedia, the free encyclopedia

Again, I urge you to read this. Pay particularly close attention to the "design" section -- the figure in that section actually shows the power guard topology (right hand side). If you don't believe me, I urge you to read McIntosh's patent that I also linked to. All the information you need has been presented to you.



> You guys don't understand it so lets put it in this box with the other amplifiers to help understanding. Wrong idea!!! You can't drive a Mcintosh to distortion with PG activiated, it's impossible. You can take a 100 watt Mcintosh and put it up against a 1000 watt Mcintosh. The difference between the 2 will be volume output only.


"Volume output", in this context, refers to a _change_ in volume of a dynamic signal. As McIntosh clearly explains, their circuit operates like all other brick wall limiters -- it kicks in when the output exceeds a threshold, and kicks off when it doesn't. The end result is dynamic range compression. [again, see the wikipedia link entitled "dynamic range compression" which shows the power guard topology pictured in their patent...]

You keep wanting to focus on distortion. The reduction in distortion by using a limiter is great! I've praised power guard in here for years, even recommending it to other members back in a post I made in 2010. I even use a limiter in _my own_ install. You're right, harmonic distortion is not responsible for the audible effects of a limiter. *Dynamics compression is.*


----------



## Hanatsu

If you turn PG off then increase output until it clips, then turn it on again. Will it decrease the volume...? If it does it will be audible ;P

Sent from my Samsung Galaxy 3 via Tapatalk.


----------



## AAAAAAA

squeak9798 said:


> He used basic equalization only when one amplifier's FR was outside of stated tolerance, and the listener was able to choose which amplifier received the equalization.
> 
> How many people use EQ in their systems? You are adjusting the FR of the amplifier in your own system with the addition of equalization, so why is it completely unreasonable for RC to do the same? Why is EQ in your car or house different than RC using it in his challenge? The end result is exactly the same.....manipulation of the amplifier's frequency response.
> 
> RC's challenge wasn't designed to prove all amps sound the same, it was designed to prove when amps won't sound different. It does that successfully, and isn't a scam when you understand the point of the challenge.


Not to mention that the room (or car) affects FR a TON. For good sound you have to have EQ. If you are tuning and there is a dip that needs fixing.. i tdoesn't matter if it the amps fault or the rooms... it will get fixed. (yes an amplifier's FR would have to be way off to be audible hehe)


----------



## RNBRAD

Hanatsu said:


> If you turn PG off then increase output until it clips, then turn it on again. Will it decrease the volume...? If it does it will be audible ;P
> 
> Sent from my Samsung Galaxy 3 via Tapatalk.


This is audible. I have the option as most McIntosh owners do is to defeat the PG on and off with the flick of a switch. Once you reach the point distortion level and turn it on, yes of course it drops the volume back down to the set distortion rating. But when the PG is set to begin with, this does not happen, and it engages or turns on it does it 1000x a second, I can't work my switch that fast, however this function when performed by the amp is inuadible. You just don't get anymore volume out of it. You can't discern any typical compression effects that you would on a typical limiter.


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## RNBRAD

Mark you can explain what it is till you've overloaded a database. They day you think you can hear it working, let me know.


----------



## MarkZ

I hear it all the time. Whenever I overdrive by a lot during sustained peaks, it becomes pretty evident. So did the original poster, who already explained that the music sounded compressed when he was using his McIntosh. If you can't hear it, then that's terrific. But that doesn't mean that everybody is a naive listener.


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## RNBRAD

MarkZ said:


> I hear it all the time. Whenever I overdrive by a lot during sustained peaks, it becomes pretty evident. So did the original poster, who already explained that the music sounded compressed when he was using his McIntosh. If you can't hear it, then that's terrific. But that doesn't mean that everybody is a naive listener.


You talking about the guy that was talking about the diff between the Tru amp and Mcintosh?


----------



## OSN

RNBRAD said:


> *This is audible.* I have the option as most McIntosh owners do is to defeat the PG on and off with the flick of a switch. Once you reach the point distortion level and turn it on, yes of course it drops the volume back down to the set distortion rating. But when the PG is set to begin with, this does not happen, and it engages or turns on it does it 1000x a second, I can't work my switch that fast, however this function when performed by the amp is inuadible. You just don't get anymore volume out of it. You can't discern any typical compression effects that you would on a typical limiter.


Is this only audible to people with 18 years of experience with McIntosh amps?


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## RNBRAD

OSN said:


> Is this only audible to people with 18 years of experience with McIntosh amps?


You might be missing the parameters of the conversation. I would hope anyone activating the "Power Guard" manually or trying to mimic the amps capabilities of activation versus letting the amp do it could hear it. That's the "key" to the success of the circuity. Not me operating the switch. I can't adjust it 1000x a second. If I run a McIntosh amp to clipping and I manually turn on the power guard, you won't notice the amp clipping cause it will back off the volume. So yea in this instance you can hear the difference or change. Not a question about it!!! But if we are talking about audible difference with the PG under "my control", then my bad totally missed that. Now were getting into the differences when I'm controlling it versus the amplifier. If I somehow mislead someone to thinking I could switch it manually and do it inaudibly, my bad again. Never meant to insinuate such an action. All I'm doing is verifying Mcintosh's claim and my experience. I don't think they claim it to be inaudible with manual switching, least I would hope not cause they would be wrong.


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## bassfromspace

OSN said:


> 18 years...diapers...yeah, you really don't know anything about MarkZ. He's closer to wearing them again than getting out of them. :laugh:


Power Guard is an adult diaper brand to Mark.


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## RNBRAD

McIntosh MC-501 Mono Amplifier Reviewed



> The MC-501 retained impressive control over the speakers *at any volume level*, never losing detail as the volume increased. *I never sensed any strain or heard any compressions that plagued most other amplifiers at these volumes*, the MC-501 continued *without any signs of strain *and when I put my hand on the amplifier it was warm but never hot. After playing this track a couple of times through my Martin Logan's with their powered woofers I then listened to it through the Acoustic Zen Adagio's which do not reach as low but the MC-501's were now the sole source of amplification, as with the Martin Logans' *there were no signs of strain or compression*. I continued to be impressed by the amplifiers' ability to provide such tight and detailed bass even with this frenzied track.


Surely McIntosh padded this reviewers pocket.


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## squeak9798

That's also a 500w amplifier....chances are good he never hit the PG limits under normal listening.


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## MarkZ

OSN said:


> 18 years...diapers...yeah, you really don't know anything about MarkZ. He's closer to wearing them again than getting out of them. :laugh:





bassfromspace said:


> Power Guard is an adult diaper brand to Mark.


Holy ****, I'm not that old, incontinent, or kinky!


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## RNBRAD

squeak9798 said:


> That's also a 500w amplifier....chances are good he never hit the PG limits under normal listening.


You really should read the review. Did he not say at any volume level?
*



There was never any glare, grain, compression or harshness even at volumes approaching levels that might cause my neighbors to call the authorities

Click to expand...

*


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## MarkZ

Cool.

Here is a good thread describing the differences between feedforward vs feedback compression (power guard being of the latter class). [a note of warning: post #5 is mis-attributing finite attack with feedback "lag", but that was caught later]

Compression : Feedback VS. Feedforward - Gearslutz.com

Graphically, (stole this from wikipedia...), you can see what power guard is doing here:










The second line is what happens when you turn the power guard feature off. The third line is what happens when you enable it. [power guard is a brickwall compressor with an attack between 50-100us and release around 50ms -- numbers listed in the patent -- so it would look _exactly_ like that plot if you assume the pictured signal was ~100Hz]


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## RNBRAD

I'd say that is dead on. Mark you did a lot of research and reading. Only thing missing is an audition and the "actual" PG signature. (link to the left)

MCINTOSH MA6500 - Brochure (Page 2 of 4)


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## MarkZ

All I read was the patent. Sought out some explanations/pictures to post here.

Cajunner, the DDT patent is available online too. Pretty easy to find. Does basically the same thing, if that's what you were wondering.


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## RNBRAD

Patent was pretty interesting, long though as one would expect. I wonder how this designs compares with oithers, or what makes it so "special? I thought using lamps and then the LEDS was rather interesting.


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## squeak9798

RNBRAD said:


> You really should read the review. Did he not say at any volume level?


*
I did read the review. That quote doesn't guaranty nor demonstrate that he necessarily approached the limits of the amplifier's power capabilities while listening to it, so it's utterly meaningless. Perhaps you shouldn't mistake subjective opinions for objective facts.*


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## RNBRAD

squeak9798 said:


> I did read the review. That quote doesn't guaranty nor demonstrate that he necessarily approached the limits of the amplifier's power capabilities while listening to it, so it's utterly meaningless. Perhaps you shouldn't mistake subjective opinions for objective facts.


You ever listened to a McIntosh amp when the PG light has kicked on? I didn't think so!! Theres probably not a listening session I don't kick the PG lights on on my Mcintosh amps. It's really not as difficult as you may think. I have a 500 watt Mono block McIntosh as well. But, my experience is probably just a rare and isolated one though. It's also likely McIntosh's claims are false as well and their experience is rare, isolated and of course biased. They have a horrible reputation anyway, so no risk in those claims. If your not going to take the word of one of the worlds most renowned high-end amp manufacturers, you sure the hell aren't accepting mine or anyone for that matter. So if all this is meaningless to you, then you need to experience it yourself if that's even convincing enough. Some people here are like mothers of a son that's on trial for murder. If she didn't see it, he is innocenet regardless of what the evidence says.


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## subwoofery

RNBRAD said:


> You ever listened to a McIntosh amp when the PG light has kicked on? I didn't think so!! Theres probably not a listening session I don't kick the PG lights on on my Mcintosh amps. It's really not as difficult as you may think. I have a 500 watt Mono block McIntosh as well. But, my experience is probably just a rare and isolated one though. It's also likely McIntosh's claims are false as well and their experience is rare, isolated and of course biased. They have a horrible reputation anyway, so no risk in those claims. If your not going to take the word of one of the worlds most renowned high-end amp manufacturers, you sure the hell aren't accepting mine or anyone for that matter. So if all this is meaningless to you, then you need to experience it yourself if that's even convincing enough. Some people here are like mothers of a son that's on trial for murder. If she didn't see it, he is innocenet regardless of what the evidence says.


Agree with *squeak9798*, just read the review and we have no comment stating that the reviewer approached the limits of the amplifier's power capabilities... So it might be possible that with a 500 watts per channel McIntosh amp, the PG never kicks in when listenning even to deafening volume. 100 watts per channel McIntosh car amp? Sure is 

Kelvin


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## RNBRAD

subwoofery said:


> Agree with *squeak9798*, just read the review and we have no comment stating that the reviewer approached the limits of the amplifier's power capabilities... So it might be possible that with a 500 watts per channel McIntosh amp, the PG never kicks in when listenning even to deafening volume. 100 watts per channel McIntosh car amp? Sure is
> 
> Kelvin


Semantics will get you every time, lol. True he didnt exactly say it was maxed out and of course he would have to say that the PG was on and the light was flashing. He only said "at any volume". So take that to mean whatever you want. It wasn't meant to be the smoking gun point that the PG is inaudible, nore is it even possible to make one or this conversation would of been done a long time ago. Only people that question it are those that have never heard it. Not a McIntosh dealer that won't run an amp into PG protection to verify their claim. Don't just take my word for it!!:laugh::laugh::laugh:


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## MarkZ

So you're aware, this site has a history. That history is to not take what _any _manufacturer's marketing department has to say as fact. That's one of the things that spawned the mass testing that goes on in this forum (and has since spread to other sites...). It's one of the things that years ago led many of us to openly criticize and subsequently debunk some of the claims in manufacturer's owners manuals and help pages (JL Audio's, for example). And there's even a subforum devoted to "car audio myths", that often come directly from the mouths of manufacturers. This has been the essence of our incarnation of *DIY*, and it's why some people view it as a "scientific" examination of car audio. If you view this outlook as being like a "mother of a son on trial for murder", then maybe this isn't the right forum for you?


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## subwoofery

:snacks: 

Kelvin


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## RNBRAD

Mark, your science is without a laboratory. We've had 2 different discussion and you continually have the same problem. The only input your able to share is from a book or internet links, or wiki, that's it. You have no time with the *actual* product(s) yet you continue to *speak on it's behalf*. I've even offered you to experience it for yourself so you can then personally "debunk" said claim and have actual experience with it. I think this forum is great for debunking manufacturer or MarkZ myths or whatever the case may be. There is a correct process in doing that, it's like a theory, is it repeatable under experiment with set parameters? You haven't made it this far with said product, but when you do, we all will be waiting for the MarkZ report, otherwise you have nothing accurate to say and it's all speculation. Period!!! That's exactly how rumors get started is from people like yourself then people with experience have to come in and clean up your mess just like your capacitor comment. You were telling people that capacitors don't leach any "real power" from a battery. I debunked that myth. But you didn't know, cause you have limited experience (again) with said product(s), yet you continue to speak on their behalf.

BTW: Let's debunk this ALREADY, lets put it to the test. You ready to finally put an end to it or you want to keep yappin your trap?


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## MarkZ

RNBRAD said:


> Mark, your science is without a laboratory. We've had 2 different discussion and you continually have the same problem. The only input your able to share is from a book or internet links, or wiki, that's it.


When I explain to you how something works because I have experience using that particular thing, you argue that it works a different way. Fine. So that's when I find a book or an internet link to give you to explain it in greater detail. Or I look up the _actual patent_ that you refer to, so that I can show you the circuit that you're talking about. I wasn't aware that you couldn't read schematics, so I showed you a wikipedia article that explains in layman's terms how that circuit in the patent works. I wrote a long explanation two pages ago, but you didn't read that -- it took you several pages before you even read the patent, but you felt you could still speak with authority about it. As a last ditch effort, I even posted a diagram directly on this site! -- knowing that you wouldn't click a link to that diagram -- but you didn't have any comment, even though it succinctly describes the operation of the circuit. 

I don't know what else I could do to help you figure this out. You say in one post that it's a limiter, but in the next post you say it doesn't act like a limiter. You say in one post that it produces an audible effect, but then in the next post continue to insist that it doesn't. I mean, seriously, wtf?

I don't derive my knowledge from internet links. I don't know where you got that idea. I build the friggin circuits or write the code myself, and have for years. I'm paid to do it. The links I provided are for _you_, not for me.


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## RNBRAD

I don't need explanation in great detail. You don't have experience with McIntosh Power Guard. You just don't!! Until you can show me this, then you have no experience with it. Period!! BTW that's my amp, not an internet pic of one. Oh it is also in PG protect mode. I offer real experience with said product, I didn't just read about it or take so and so's word for it. I didn't listen to another amp in it's protect mode or one similiar and claim that this one performs the same or similiar. Call me naive deaf or whatever you want, but regardless I have "actual" experience with THE discussed product.


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## MarkZ

RNBRAD said:


> I don't need explanation in great detail. You don't have experience with McIntosh Power Guard. You just don't!! Until you can show me this, then you have no experience with it. Period!!


Your logic is borked. That's like saying people who build active crossovers would have no idea how the crossovers in an Orion amp work, because they've never owned an Orion amp. Your position comes from having no understanding about what the circuit in question is. So you don't understand why someone who has experience with an active crossover in an a/d/s/ amp would also know about active crossovers in other amps.

What I've attempted to demonstrate to you -- and which I've done successfully but you refuse to pay attention -- is that the McIntosh power guard feature is a limiter. You even said you didn't dispute this earlier. So your "you have no experience!" mantra that you hang your hat on _in every thread_ doesn't fly here, because I have pretty extensive experience using and designing these circuits in a variety of applications -- including in my own car audio system.

So, instead of trying to obfuscate with that sorry "you have no experience!" excuse, while offering nothing else of substance, why don't you actually discuss the principles of operation?


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## subwoofery

Love this... :snacks: <-- anyone wants some? 

Kelvin


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## RNBRAD

Let me ask you one question MarkZ? If a person comes up to you and asks about a McIntosh amplifier and in particular the "Power Guard" feature. They ask you, Mark is this thing audible? What's your reply?

From what we've talked about here, your going to tell them it's audible. This is what really miffs me about people like you and car audio. Misinformation is rampant especially among those with no experience with it and yet they are readily willing to put into a box, just as you are. That is all kinds of wrong, I can't even fathom. I feel sorry for those new guys that come in here and look up to you with all your posts and think you actually know something when in actuality, you can only speak through reference. Are you effin kidding me bro!!!!!!!! You don't like me cause I've called you out twice and both times your DEAD wrong!!!! If someone asks you about the performance of a PG on a McIntosh amplifier, the correct answer is to send them my way cause you have no effin clue!!!! 

You think I should read the patent again? Should we break it down to the fine details of operation? Maybe I missed something. OMG spare me, just listen to the flippin thing already!!!

BTW we are not talking about a universal product everyone uses. It's a patented product, and no it is not exactly like other compressors.


----------



## MarkZ

RNBRAD said:


> BTW we are not talking about a universal product everyone uses. It's a patented product, and no it is not exactly like other compressors.


Then you can begin by explaining how it's different. Which was the question I asked you in post #130.


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## RNBRAD

The speed at which it operates.

You think you can hear it? Well of course you do, what am I thinking.:surprised: You ready to put it to the test and prove your point and disprove mine?


----------



## MarkZ

RNBRAD said:


> The speed at which it operates.


Bzzzzt. Try again. It's an analog circuit. It operates at the speed of light (well, more accurately, at the effective slew rate of the system). So does every other limiter. :laugh:

I know what you're getting at. The marketing materials say 1000 times a second, as if that's some sort of impressive feat. But what they're really referring to is the integration time of the comparator, which is set by choosing a particular value of a capacitor. This is actually a fairly slow number. Which isn't a bad thing. It is what it is. Conventional limiters give you a knob to control this value.

Your answer tells me that even after all my explanations and all my links to educational materials, you _still_ don't understand how in the hell this thing works. That's ok. But don't tell me it's functionally distinct from limiter circuits when you don't know how limiters work!

And you had the balls to say that _I_ don't know anything?? :laugh:


----------



## RNBRAD

So what your saying is that I can place an oscilloscope on any amplifier with a compressor and I shouldn't be able to see any clipping of the signal? Is that correct?


----------



## MarkZ

RNBRAD said:


> So what your saying is that I can place an oscilloscope on any amplifier with a compressor and I shouldn't be able to see any clipping of the signal? Is that correct?


Assuming the compressor is set "correctly", you won't see any clipping within the time resolution dictated by the attack setting. According to the patent, the attack is set to 50us for powerguard IIRC.


----------



## RNBRAD

Can you show me an amplifier with a faster attack than 50 microseconds, brand, and is it audible? On a Mcintosh amp the clipped signal will never make it to the output phase. A lot of amps adjust after the clipping starts and then reacts to the overload in question after it is already made it to the output circuitry.


----------



## Golden Ears

RNBRAD said:


> You ever listened to a McIntosh amp when the PG light has kicked on? I didn't think so!! Theres probably not a listening session I don't kick the PG lights on on my Mcintosh amps. It's really not as difficult as you may think. I have a 500 watt Mono block McIntosh as well. But, my experience is probably just a rare and isolated one though. It's also likely McIntosh's claims are false as well and their experience is rare, isolated and of course biased. They have a horrible reputation anyway, so no risk in those claims. If your not going to take the word of one of the worlds most renowned high-end amp manufacturers, you sure the hell aren't accepting mine or anyone for that matter. So if all this is meaningless to you, then you need to experience it yourself if that's even convincing enough. Some people here are like mothers of a son that's on trial for murder. If she didn't see it, he is innocenet regardless of what the evidence says.




OK... its one of those.."you are both right" under certain conditions.

So here is a interesting test.

Get both the 16 Bit 44.1khz redbook CD, and 24 bit 192kHz or 96kHz recordings of Santana "Super Natural"

This ablum used a TON of compression in the Redbook CD format. It's fricking awful....a sin.

Record producers were pushing for songs to be recorded with more compression so they "sound louder" on the radio.

They pushed it way up on this album. 16/bit 44.1kHz version.

Now go get the 24/96kHz version... they remastered it with more Headroom, less compression.

Take that version and downsample it to 16bit/44.1kHz (which is not a conversion in its favor because it is not an even interger conversion..if it were a 88.2kHz it would be a better down conversion than from 24/192 or 24/96). Pick a song with the most dynamic range from the 24 bit version prior to downsampling.

OK so you now have a compressed 16/bit 44.1 version and a less compressed 16 bit 44.1 (down-converted one) versioin.

Play the compressed 16/44.1 at full output on a McIntosh (I own 5 of their amps) and drive the powerguard circuit to light up. You probably won't hear any difference at all because the difference between the loudest and quiest parts on that CD is minimal. The PG circuit will be inaudible.

Now play the version with dynamic range and when you drive the circuit into clipping some of the time.... not lit up all the time... what you will hear is that version starting to sound like the compressed version.

You will hear the PG circuit start to reduce your dynamic range betwen the quietest and loudest passages. But you won't hear distortion. Which ...is a pretty good compressor..in terms of the sonic cost. 

SO with highly compressed music , PG should be inaudible because there was no dynamic range to be lost in the first place.

All that being said...I don't even listen that loud anymore, but prefer my amps to run at 5-15% of their rated wattage...I postulated that it might be the loss of crossing distortion as class A/B amps would run class A in that range. It works for me with McIntosh amps because the distortion is even low at low levels.

In regards to speaker distortion being higher... which it is,,,, it also matters where that distortion falls as our hearing is not linear, and is more sensitive to distortion at certain frequencies, as well as even vs odd order distortion having different perceived effects.

So an amp with higher measured distortion in certain frequency ranges with Even ordered distortion could sound better than another amp with less measured distortion..but with that distortion falling in an area where the ear is more critical, and also depending on the type of distortion. 


Now here is an area where I am not sure if what I am saying is accurate.
A US Amps Hybrid Tube amp design might have advantages in a car application.
Many high current Car amplifiers have little trouble delivering more current provided that the power supply from the car is ample. This is a limiting factor in some home systems with inefficient speakers running off a 15A home circuit. Some People (and this is extreme) put in 40 amp 220vt circuits to lessen the effect of current limiting. Voltage is not a limiting factor in a home system, but perhaps it is more of a factor in a car system. Tubes are great at producing voltage, but not so great in producing current (Uness you have a ton of them and a huge power supply). So a hybrid amp might have good current ability like a higher current design, as well as good voltage like a regular tube design. I had a BK Butler designed Butler 5150 hybrid tube amp- with his thermionic circuit, which probably was not a higher votlage design like your US amps tube hybrid.. but there was something going on there. Again this paragraph is not an area of expertise, so look at it as a guess not gospel. All that matters is you found something that you enjoy more, so all amps are not the same.



As an aside.. The ideal thing IMHO would be one that scans the entire musical passage- determines the loudest level without needing compression and gain limits to that point. Something with todays processor speeds is EXTREMELY easy to do... for instance using Traktor Pro 2, a dj software program, I can click and instantly see the entire waveform and make adjustments as I see fit.. And it loads the song from apple lossless ALAC in about .5-.7 of a second.

Similarly, if Richard Clark's amp test uses a recording with limited spacial cues, and limiting quality speakers, in a loud car with lots of induced noise ...it might mask the differences between a excellent amp and a crappy amp. Certainly, if I was listening to Brown Sugar by the Rolling Stones running with 1 watt of output (on Manhattans East Side IRT subway line) ...I lcould not tell the difference betwen a Class D $200 amp and Tru amp or my McIntosh amps. But I can readily tell the difference in my home rig between a 1975 Bryston 4B and a 1982 Bryston 4B. I wanted to just vertically bi-amp them, but found one to sound lifeless compared to the other but both amps were up to spec. So the Newer amp went on top and I had to horizontally bi-amp instead....always annoyed me..I swapped them a few times trying to make it work, but always was annoyed by one lifeless channel side. My crossover frequency was 140 cycles, and I would never be able to hear the difference with the worse quality one on the bottom.

So all I am saying is if you present a test, make sure that it is a test which can show differences if they exist and not mask them.


my 2 cents.


----------



## masswork

RNBRAD said:


> Can you show me an amplifier with a faster attack than 50 microseconds, brand, and is it audible? On a Mcintosh amp the clipped signal will never make it to the output phase.


50us attack time? Never make it to the output phase?

Care to explain?


----------



## AAAAAAA

Markz, you are arguing something way over his head... when his replies are basically "look at what this marketing litterature says" and "my many years of blah blah blah"..... it's pretty much done.


----------



## masswork

cajunner said:


> But it's Mark saying that all limiters work the same.
> 
> So it's on Mark to prove that McIntosh Power Guard is not a better implementation of limiting devices.
> 
> 
> And, I don't see where he does that, he says that the rest of compressor/limiter designs have to be set by adjustment, and McIntosh has a static 50uS of hold, so it should be demonstrably worse than one that you can tailor to the specific needs of the system.
> 
> 
> But, maybe it's not just that simple, maybe Power Guard does something that a guy controlling a knob doesn't, or can't do.
> 
> that would be a better version of a limiter, and exactly what is being argued against.
> 
> so which is it, then?


Yeah, a Mcintosh schematic will be very helpful.
I assume it's an analog compressor/limiter.


----------



## AAAAAAA

cajunner said:


> But it's Mark saying that all limiters work the same.
> 
> So it's on Mark to prove that McIntosh Power Guard is not a better implementation of limiting devices.
> 
> 
> And, I don't see where he does that, he says that the rest of compressor/limiter designs have to be set by adjustment, and McIntosh has a static 50uS of hold, so it should be demonstrably worse than one that you can tailor to the specific needs of the system.
> 
> 
> But, maybe it's not just that simple, maybe Power Guard does something that a guy controlling a knob doesn't, or can't do.
> 
> that would be a better version of a limiter, and exactly what is being argued against.
> 
> so which is it, then?


he pretty much already answered all of those questions... The point is that limiters do all the same thing slightly differently : compress the sound which is always audible no matter the circuit when overdriven within the audible range IE guestimating 2db of compression or more.


----------



## RNBRAD

cajunner said:


> understanding limiters and not having it demonstrated in person, is like book smart versus common sense.
> 
> limiters aren't all the same, but their effects seem to be lumped in together whether the circuit is a better or worse implementation.
> 
> I say McIntosh's implementation is the best available, and nothing I've read says different.
> 
> now, with that you can go wherever you want.


Exactly my point. I don't really care to explain how the PG fully works nore will I ever fully understand it or care to. I just know it does work and damn good, but one thing I do understand is that this puppy is not your typical "brand x" compressor. But then again people will argue the sound differences of cables so why should a compressor be any different.


----------



## MarkZ

cajunner said:


> But it's Mark saying that all limiters work the same.
> 
> So it's on Mark to prove that McIntosh Power Guard is not a better implementation of limiting devices.
> 
> And, I don't see where he does that, he says that the rest of compressor/limiter designs have to be set by adjustment, and McIntosh has a static 50uS of hold, so it should be demonstrably worse than one that you can tailor to the specific needs of the system.
> 
> 
> But, maybe it's not just that simple, maybe Power Guard does something that a guy controlling a knob doesn't, or can't do.
> 
> that would be a better version of a limiter, and exactly what is being argued against.
> 
> so which is it, then?



I'm sorry I haven't "proven" it to you sufficiently. I'm not sure what else you'd like me to provide. ???

1) I've provided a link to the patent, which shows a flowchart, a schematic, and the relevant parameters.
2) I've provided a link to the wikipedia page on dynamic range compression, which describes in layman's terms a class of feedback compressor that directly matches that shown in the patent.
3) I attempted to describe the same in layman's terms in a reply to you earlier in the thread.
4) I embedded a picture in this thread (again from the wikipedia site) which shows what different classes of compressors do to an input signal.

Do you have any _specific_ questions that lead you to believe this compressor is doing something special that I haven't already addressed? I talked about this circuit's advantages in this thread and others. I talked about why it's a *great feature*. I even mentioned briefly why I personally use it in my audio system! But I also talked about what it can't do.

On the bright side, I'm glad that people are finally talking about compressors in audio reproduction. It doesn't get much airtime around here. Very few people use it for playback. Even fewer use it in car audio. I think it has some usefulness, especially for power-limiting in low frequency drivers.


----------



## MarkZ

RNBRAD said:


> Can you show me an amplifier with a faster attack than 50 microseconds, brand, and is it audible? On a Mcintosh amp the clipped signal will never make it to the output phase. A lot of amps adjust after the clipping starts and then reacts to the overload in question after it is already made it to the output circuitry.


Any compressor with a reasonable attack range. Including guitar pedals and free software. I don't know of very many compressors that _don't_ have attack times that quick, although I'm sure they're out there.

The key is actually not the attack time, but the threshold signal. The McIntosh triggers on a pre-set THD, which is computed by the comparator circuit. Most others trigger on a pre-set number of samples that exceed a threshold you dial in (feedforward compressors). Some others use side chaining to define threshold, which is the same concept as the McIntosh. Others manipulate the side chain signal so as to minimize certain artifacts (ie. "side effects"). And some are flat-out feedback compressors, which is what the McIntosh is. The advantages to this come when it's built into the amp, which most are not.

But none of these things describe what it _does_ to the signal. Only what triggers it. They all do either hard limiting, soft limiting, or compression with a soft knee. And all of _those_ have the same effect on the input signal, only to varying magnitudes and time constants (which are all settable in conventional compressors).

So what's special about the McIntosh? It's already optimized for you. That's a big deal. Sort of like how the MS-8 will tune itself. For most users that's a pretty good thing. But people who know how to tune systems don't necessarily need that. Just like how people who know how to use compressors don't necessarily need power guard.


----------



## MarkZ

Golden Ears said:


> OK... its one of those.."you are both right" under certain conditions.
> 
> So here is a interesting test.
> 
> Get both the 16 Bit 44.1khz redbook CD, and 24 bit 192kHz or 96kHz recordings of Santana "Super Natural"
> 
> This ablum used a TON of compression in the Redbook CD format. It's fricking awful....a sin.
> 
> Record producers were pushing for songs to be recorded with more compression so they "sound louder" on the radio.
> 
> They pushed it way up on this album. 16/bit 44.1kHz version.
> 
> Now go get the 24/96kHz version... they remastered it with more Headroom, less compression.
> 
> Take that version and downsample it to 16bit/44.1kHz (which is not a conversion in its favor because it is not an even interger conversion..if it were a 88.2kHz it would be a better down conversion than from 24/192 or 24/96). Pick a song with the most dynamic range from the 24 bit version prior to downsampling.
> 
> OK so you now have a compressed 16/bit 44.1 version and a less compressed 16 bit 44.1 (down-converted one) versioin.
> 
> Play the compressed 16/44.1 at full output on a McIntosh (I own 5 of their amps) and drive the powerguard circuit to light up. You probably won't hear any difference at all because the difference between the loudest and quiest parts on that CD is minimal. The PG circuit will be inaudible.
> 
> Now play the version with dynamic range and when you drive the circuit into clipping some of the time.... not lit up all the time... what you will hear is that version starting to sound like the compressed version.
> 
> You will hear the PG circuit start to reduce your dynamic range betwen the quietest and loudest passages. But you won't hear distortion. Which ...is a pretty good compressor..in terms of the sonic cost.
> 
> SO with highly compressed music , PG should be inaudible because there was no dynamic range to be lost in the first place.


This is all pretty much true. At the same loudness setting, the compressed music file won't trigger power guard as often because it's already been compressed. Now, if you set those files to the same _peak_ level instead, then that's a different story. 



> All that being said...I don't even listen that loud anymore, but prefer my amps to run at 5-15% of their rated wattage...I postulated that it might be the loss of crossing distortion as class A/B amps would run class A in that range. It works for me with McIntosh amps because the distortion is even low at low levels.


Haha then why don't you just use class A amps?

In car audio it's hard to find high biased class A/B, and it's even harder to find class A amps (and probably impractical). So we're either stuck with class B implementations, or a few lazy class A/B. I don't think it's a big issue, personally, but whatever floats your boat, you know?



> In regards to speaker distortion being higher... which it is,,,, it also matters where that distortion falls as our hearing is not linear, and is more sensitive to distortion at certain frequencies, as well as even vs odd order distortion having different perceived effects.
> 
> So an amp with higher measured distortion in certain frequency ranges with Even ordered distortion could sound better than another amp with less measured distortion..but with that distortion falling in an area where the ear is more critical, and also depending on the type of distortion.


Yup! When some of these guys run tests on speakers around here, they usually provide distortion graphs that show distortion as a function of frequency, and they're usually separated out into f2, f3, etc. That's way more informative than a single THD number. So if someone on this site felt compelled to start testing amps, I'd hope that they'd provide the same information.




> As an aside.. The ideal thing IMHO would be one that scans the entire musical passage- determines the loudest level without needing compression and gain limits to that point. Something with todays processor speeds is EXTREMELY easy to do... for instance using Traktor Pro 2, a dj software program, I can click and instantly see the entire waveform and make adjustments as I see fit.. And it loads the song from apple lossless ALAC in about .5-.7 of a second.


I agree again. This is the ideal. But it's also not real-time, so it would be difficult to implement with analog circuitry without introducing a whole song-worth of lag. :laugh: Still, it wouldn't be hard to implement in a properly-calibrated digital playback system. Foobar2000 (which I use as a player) has the replaygain feature which does something similar, but it doesn't compress, it just normalizes. This would actually be one of the rare cases where setting gains to 0dB would be advantageous. 



> Similarly, if Richard Clark's amp test uses a recording with limited spacial cues, and limiting quality speakers, in a loud car with lots of induced noise ...it might mask the differences between a excellent amp and a crappy amp. Certainly, if I was listening to Brown Sugar by the Rolling Stones running with 1 watt of output (on Manhattans East Side IRT subway line) ...I lcould not tell the difference betwen a Class D $200 amp and Tru amp or my McIntosh amps. But I can readily tell the difference in my home rig between a 1975 Bryston 4B and a 1982 Bryston 4B. I wanted to just vertically bi-amp them, but found one to sound lifeless compared to the other but both amps were up to spec. So the Newer amp went on top and I had to horizontally bi-amp instead....always annoyed me..I swapped them a few times trying to make it work, but always was annoyed by one lifeless channel side. My crossover frequency was 140 cycles, and I would never be able to hear the difference with the worse quality one on the bottom.
> 
> So all I am saying is if you present a test, make sure that it is a test which can show differences if they exist and not mask them.


True, but I think the "challenger" gets to choose the program material.


----------



## [email protected]

RNBRAD said:


> Exactly my point. I don't really care to explain how the PG fully works nore will I ever fully understand it or care to. I just know it does work and damn good, but one thing I do understand is that this puppy is not your typical "brand x" compressor. But then again people will argue the sound differences of cables so why should a compressor be any different.


How can you explain it if you dont fully understand it?


----------



## SaturnSL1

subwoofery said:


> Love this... :snacks: <-- anyone wants some?
> 
> Kelvin


Grab me a beer next time you refill the popcorn, please. I don't wanna miss anything


----------



## RNBRAD

BeatsDownLow said:


> How can you explain it if you dont fully understand it?


Cause I have real (listening) experience with the exact product. Not just an audition but years in the drivers seat. Just as if you were to tell us about your new cars performance. Do you know the timing and duration on the valves of the car you drive right now? And really how fully does someone understand it? Am I going to judge a speaker solely on its build design parameters or am I going to listen to it. If you ask me about speaker X in my car and how it sounds, I probably won't have the T/S parameters handy nore will I have the speakers blue prints. Mark even posted a link that showed the brick wall compressors at those attack times are best for protect functions only cause they sound so bad. Is this the case here?


----------



## chefhow

SaturnSL1 said:


> Grab me a beer next time you refill the popcorn, please. I don't wanna miss anything


X2....


----------



## SaturnSL1

RNBRAD said:


> Just as if you were to tell us about your new cars performance. Do you know the timing and duration on the valves of the car you drive right now? And really how fully does someone understand it?


A lot, if not most manufacturers don't give that kind of information. If you want to know the duration of your cams you're going to have to get your hands dirty. However, it isn't difficult to understand. I'd say working on cars or building performance engines is a lot easier than understanding half of the stuff in this thread.


----------



## RNBRAD

This is a response from McIntosh labs, I held the name, didn't feel that was necessarily relevant or appropriate. But if someone feels the need to contact the individual, feel free to PM me. 

I sent a letter to Mcintosh Labs, asked if the Power Guard was the same or different from the standard compressor and if so how? Also if the compression and distortion was audible or inaudible and if they were inaudible how? Here's their response to me. I can't post the graphs cause it is in a PPS format, less someone knows how to. Glad to email them to you. Anyway take it for what it's worth, just don't kill the messenger if this information does not greet you well or is not congruent with your readings. 

*"Hi Brad, 

Power Guard is a waveform comparator, comparing the input to the output, it activates when it sees the signal has been distorted, riding the gain so over drive does not cause distortion. 

See the attached measurements showing very little change with power guard activated at 14dB of over drive ( that is a lot, like sending a signal well over twice the maximum input voltage) . 

Unlike a compressor, it does not kick in at a predetermined level, if power from the wall is low, the amps power supply caps will run out of juice early and cause distortion, and power guard will kick in, if you have tons of power from the wall, the amp might hit 4 or 5times rated power before the caps run low and distortion occurs. 

You can not hear it because the signal in power guard is only changed a very little bit, mostly a tad more harmonic content as illustrated in the attached power point, also because it will kick in/out way faster than your ears can catch." *


----------



## Golden Ears

The reason I under drive The class a/b Amplifiers is so that they run cool most of the time, With very little current draw As opposed to class a ampswhich run fulltilt all the time. And for those times when I want to step out of the car and let someone else blow their head off, I'm only so eager to do so.

One other thing I hadn't thought about until reading this thread, was that I could use power guard on my Macintosh amplifiers, and just use amplifier power to match the speaker rated power wattage (Even though we know that number doesn't mean much) And I might have less fear of over driving my speakers. Even with proper gain structure, there is so much variability in recordings nowadays, a limiter is still very useful

In this instance having this feature is helpful.

Because this is a big hobby of mine, I don't mind spending more money on it than I should.

But when talking to other people what I really want to know is how to make a very inexpensive amplifier sound like an expensive tube amplifier Or an expensive solid-state amplifier.

In essence I would like to know what exactly Richard Clark does to "tune" one amplifier to sound Exactly like another. Not so much for my purposes, but more for my friends that always ask me advice.

I would love to use an old a/d/s power plate and some peerless SLS and some SB Acoustic speakers, Along with a portable digital to analog converter To give them great sound for next to nothing.

All that being said, I have used mcintosh car amplifiers to test speakers indoors And they have driven magneplanar Tympani's, as well as some other large floorstanding dynamic speakers with ease And finesse. Most oddly, perhaps because I'm running them off the battery and feeding and very clean power, I find that I like the sound of those amplifiers a little bit better than the home amplifiers which sounded less Involving run off a 15 amp 110vt circuit


----------



## MarkZ

RNBRAD said:


> Unlike a compressor, it does not kick in at a predetermined level, if power from the wall is low, the amps power supply caps will run out of juice early and cause distortion, and power guard will kick in, if you have tons of power from the wall, the amp might hit 4 or 5times rated power before the caps run low and distortion occurs.


"Unlike a compressor"...

Maybe you should send them that wikipedia page? :laugh: The second half of that page describes comparator-based compressors. They exist! Honest!  



> You can not hear it because the signal in power guard is only changed a very little bit, mostly a tad more harmonic content as illustrated in the attached power point, also because it will kick in/out way faster than your ears can catch." [/B]


Yup. They're referring to pumping here. You probably won't hear it. But then again, you won't hear it if you set a conventional compressor "correctly" too (or just mimic McIntosh's parameters). But like I said a zillion posts ago, we're not talking about artifacts (or "side effects", as McIntosh calls them). We're talking about dynamic range compression. When I've been saying "audible", that's what I've been referring to. Like I said in post #130, when they say that the side effects are inaudible, I believe them. That doesn't mean that power guard doesn't introduce compression though. It means it doesn't introduce pumping. And presumably it has the high frequency issue worked out, but so do most modern compressors with side chaining.


----------



## MarkZ

cajunner said:


> ahh, nuts and bolts.
> 
> 
> I like it.
> 
> Now, the patent on this particular method of compression, or limiter, is because....
> 
> 
> the patent office was being generous that day?
> 
> 
> the patent office, tired of reading about different limiters, just gave McIntosh a gimme?
> 
> a mulligan, is that what happened?
> 
> 
> yeah, I think McIntosh should have a clue as to what they were paying a patent fee for, considering they were the ones sending in the application, lol...


Have you ever patented anything? 

Incremental gains. DDT is a very similar approach. They have a separate patent too. All you need to do is modify something, and you can patent it. Ask pharm companies. 

Have you read the patent yet?


----------



## MarkZ

Golden Ears said:


> The reason I under drive The class a/b Amplifiers is so that they run cool most of the time, With very little current draw As opposed to class a ampswhich run fulltilt all the time. And for those times when I want to step out of the car and let someone else blow their head off, I'm only so eager to do so.
> 
> One other thing I hadn't thought about until reading this thread, was that I could use power guard on my Macintosh amplifiers, and just use amplifier power to match the speaker rated power wattage (Even though we know that number doesn't mean much) And I might have less fear of over driving my speakers. Even with proper gain structure, there is so much variability in recordings nowadays, a limiter is still very useful


Exactly what I use mine for.


----------



## RNBRAD

Mark, the Wiki page also said the sonic results of the type of compressor McIntosh uses has the worst audible affects and is harsh and unpleasant with anything more than unfrequent activation. Kinda like reading through all that capacitor jargon, doesn't matter what it said, fact still remained. Thing with caps, the ability to prove it without listening was pretty easy. Audibility or inaudibility of something is hard to prove on paper. That's why hearing is believing.

I think what's interesting is the PG activates based on reserve power of the internal capacitors. Wonder about external as well since I run those too? Not only that but it activates and deactivates in as little as 1/200 of a second (speed of circuitry) and also triggered by minute increases in distortion and not at any predertimed power level. I think the key being missed is not just the performance of just the Power Guard circuitry, but also the performance of the amplifier when combined with this feature. There's a combination of factors coming to play here and feel that no other amplifier and compressor can duplicate as far as detail in audible experience. That's why you can't hear the distortion or compression. It's not like I don't listen to my system at the edge of clipping, cause if my PG isn't flickering, it's not me listening to it. I also listen to a lot of Telarc recordings to avoid your typical compression found in a lot of music today. I find them very enjoyable but you better have the volume button close by.

I remember when I first bought these amps I wired in the PG defeat switch under the dash. After a while you forget which way is off/on. The Power Guard lights up regardless if it's defeated or not. Only way I could tell is to max out the volume till the PG light is pegged, hit the switch over and over listening several times for a subtle drop in bass output. Can't hear compression as you would think in any of the upper freq range, actually sounds phenominal!! One thing I will try though is the 16bit vs 24bit recording. I have plenty of 24 bit recordings but I'll have to run RCA's over from my other car so I can play DVD-A format with some very dynamic recordings from Blue Man Group. Might be interesting.


----------



## RNBRAD

I found this very interesting about compressors in general, cause I believe there are literally thousands of different units, and only a handful regarded as superior performers. I feel that the experience with compressors in this thread is actually from misuse/improper use of them or even junk. When used correctly, not just the PG, they shouldn't be audible at all. Wiki even mentions that. How ironic is that?? :laugh::laugh: As you read, I think this also confirms why a clean McIntosh amplifier is key to the success of a compressor and vica versa. So properly implemented, it should be transparent, inaudible, combined with no audible distorted output of the McIntosh amp, the Power Guard circuit when activated should be inaudible. Reason is, "it is" done correctly. This reminds me of capacitors. So much junk and misuse of the product, everyone just assumes the performance standards based on what most experience. This is exactly the case with compressors as well. Reference at bottom.



"Part of the problem is that people expect to hear the compression working, or hear some magic improvement to their tone (extra "fatness" for example), so they turn it up until they can hear a big change. But most of the time the correct setting of a compressor is found when you can't hear it working. Extreme compression can be useful and cool-sounding in some specialized circumstances; but the vast majority of the time you'd actually benefit most from a transparent "invisible hand" keeping your levels under control without messing things up. And that requires lighter settings. If there will be any tonal improvements from the compressor, expect them to be very subtle.

When people post that they hate compression because they are "very dynamic players", or because they prefer to "really hear the difference between light playing and loud playing", I respond that if they were using compression properly, the audience would actually hear their dynamics even better, that in fact compression is a tool not for killing dynamics (unless you want it to) but for making dynamics even more articulate and audible. Here's how that works:
When playing with wide dynamics, there are two main things that "change sound" going from light touch to heavy strike: the strings, and the clipping of the amp rig (for example tube/transistor distortion/compression, speaker driver compression, and transformer sag). 

The strings obviously vibrate differently as you play differently, and may rattle against the frets. They will make all of their tone changes completely regardless of whether you have a compressor in line--those changes are controlled entirely by your hands, and have no direct relationship to the level of the signal. You can change the volume without altering the tonal effect of dynamic playing of the strings.

The amp gets more or less distorted or compressed in normal operation, without necessarily having any obvious overdrive effect or compressor feature. The amp will clip/sag based entirely on the level of the signal. So for people who play tube amps loudly for example, a compressor really will have a negative impact on the dynamic sound that player is accustomed to. But for people who play clean, expecting no amp distortion, there's no impact. So my comment about making dynamics easier to hear is aimed at clean-tone playing, not clipped-amp playing.

Given a clean amp, with all dynamic tonal changes coming from the strings, you then have your "quiet tone" playing at a very low actual volume level, and your "aggro/strong tone" playing at a very loud actual volume level. But you want the audience to hear both of those equally well! You don't want the quiet stuff to be lost unheard, and from a practical standpoint you don't want the loud stuff to blow your speakers. Compression, done properly, brings up the audible level of the quieter playing, making it easier to hear subtle details, without taking away the "feel" and tone of softer plucking. And by reducing the height of the stronger signal peaks, you get the freedom of really digging in to the strings for an even more dramatic dynamic string tone, without as much concern about damaging your cones, and without "making" the soundman turn you down in the PA mix.

In other words dynamic playing is as much about tone as it is about volume, and getting the most out of your dynamic playing can mean maximizing the amount of tonal change your audience actually hears and appreciates, and that can mean reducing the changes from maximum to minimum volume, with compression.

When playing with wide dynamics, there are two main things that "change sound" going from light touch to heavy strike: the strings, and the clipping of the amp rig (for example tube/transistor distortion/compression, speaker driver compression, and transformer sag)."

Killed my tone


----------



## fischman

I'm siding with Markz and Golden Ears on this one. Distortion and other artifacts would be inaudible with PG. However, if you took a 1khz tone, recorded at a very low level and then had that tone jump to a 0db level and then dropped it back down to the lower level, then took that recording and played it with the low level tone played at a level where the input voltage to the amp was just below kicking on the PG. Would you notice the extreme jump in volume when the level went to the 0db recorded portion? Or would the compression from the PG minimize that jump to avoid the amp being pushed into clipping/distortion. 

If the answer is that the amp would not provide the power to give you the full jump in output, then PG is audible. If it can somehow still provide the full increase in output while avoiding clipping/distortion, then you have the magic pixy dust I'm looking for.

Let's say the Mcintosh amp in a specific setup would start clipping/distorting at just over 100w. In the test above, the low level output would be playing at 100w, when the jump in recorded level happens, either PG would kick in and compress the volume to keep it at 100w output, or the amp somehow pushes more power than it could before without the clipping/distortion. If you used the 200w amp Markz referred to earlier, and set it up to play at 100w with the low level tone, when it spiked, it would have much more wattage to provide to that spike(although it would only amount to 3db increase). 

This is also why there isn't much difference in loudness between the PG being on or off. With it off, distortion and clipping may occur, however even a jump of another 100w would only provide a 3db bump in volume. With todays highly compressed music, I would say it would be hard to tell the difference between compressed recordings or compressed output from the amplifier. If you took some extremely dynamic symphony music and played it over the system at maximum volume, I would imagine you would be able to tell the difference between a system using PG, compressing the peak volume, vs a system without PG or one utilizing more power.

RNBRAD, you even said yourself earlier in the thread that volume is the difference, volume is audible, and this is what would be limited by PG. Mainly Peak volume on extremely dynamic songs as Golden Ears pointed out. PG is excellent and removing distortion but at the expense of dynamics when average output is near the max distortion output level. 

Josh


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## fischman

RNBRAD said:


> In other words dynamic playing is as much about tone as it is about volume, and getting the most out of your dynamic playing can mean maximizing the amount of tonal change your audience actually hears and appreciates, and that can mean reducing the changes from maximum to minimum volume, with compression.


Although true, I would rather have a speaker/amp setup that can provide an accurate representation of both the tonal and the volume changes. What is quoted above is correct in creating something that sounds good at the tradeoff of actual volume dynamics. This is a compromise, but is not accurate to the source. If the soft note to the loud note increases by 20db, why would I want to compress that to 10db, or 3db, or in worse case scenarios, 0db. I would rather spend my money on additional power and speakers that can handle it to keep the full dynamic change of volume while maintaining the correct tonal characteristics. 

Josh


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## RNBRAD

Josh, thanks for your input and opinion. I honestly see where your coming from and totally understand it. I think we want to put this amp/compressor system under very set parameters and then contemplate as to whether it would be audible then. I still don't think so. Reason why is because even though the PG is activated the Mcintosh amp is not out of power, its not stopping the peak transients, and possibly far from it. Like the response from Mcintosh, it mainly has to do with the power in the capacitors. I think even when the PG is activated it attenuates on the input side at around 0.5% distortion but the amp will continue to make power till it has reached a distortion of around 2%. The output I'm sure during peak transients, these caps deplete and increases distortion, at a split second the PG is activated and most likely turned off in 1/200 of a second until it recovers. This amp does not play at max like a motor bouncing off the rev limiter. It always has the ability to over-rev persay, so it always has the headroom to breath. The problem though is the amp will not gain volume, "by your control" it will gain volume based on music content or dynamics but you can't ring it out above a point input wise. PG does not turn the volume down or an audible decrease in volume output, not even close. Then again I reiterate, it stops the input side to a point while still maintaining dynamics on the output side. Does this make sense at all? Kind of like my analogy with my home unit I gave earlier in this thread. You reach a point, the volume increase is done, but at the point it is still dynamic as if the volume was set to halfway of any other amp. 

Let me add another anology. Take a 1000 watt amp, it will perform at 1000 watts but your volume will only dial to the 750 watt range. When you hit 3/4 volume (on the dial) its done, but the amp is not done. You have no idea you have hit a wall audibly speaking. That is exactly to a tee how this amp performs. Does that make a lick of sense?

Also at the time the PG kicks on early in the distortion phase to the "no more power" is probably a big power gap, probably more than a lot of amps make. Combine this with the speed of activation and deactivation, performance of PG and the amp and then I think it's easier to understand. But really, thse amps perform like very large amp at 1/2 volume. But at 1/2 or 3/4 no more input but output they will perform to full rated power and above and do it ultra clean and transparent.


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## RNBRAD

One thing to note about the PG is it acts early like I said, at around 0.5% distortion, it allows plenty of headroom for this amp to play. There is also a second phase where the actual subtle compression takes place. It's like the soft knee compressor or elbow, thing is this amp never really reaches that phase because of the input control of the PG. I think this is key, it acts early versus late giving the amp plenty of room to operate in its upper limits without all the ill effects of compression and distortion. I've learned a lot about these amps over the last week or so, thanks to this thread. Also realized these amps are cleaner than they are rated because distortion rating equipment is not as accurate as these amps. 

I totally understand the theory of it though. In laymans terms, if this amp is operating at 99% and the next dynamic signal to be accurate requires this amp to perform at 105% which is impossible without audible artifact, compression etc. Trust me, these amps don't operate that close to the wall. They have plenty of room to power the transients under the distortion and compression envelope.

I know we can run into problems trying to explain audible experiences. It's really subjective, but I think this is more objective than you think. I do have the actual measurement in PPS if you would like to view them. It looks like all changes the pG makes in terms of DB volume is under the audible envelope then couple in the early and speed of control and very short duration (1/200 of a sec), just no way to hear it happen. It's immediately turned off when not warranted.

Also I believe I read PG controls the input linearly, so this would maintain the dynamics on the input side although it would control total volume on the output side. But like I said, it's too fast to hear any volume changes, meaning when you hit a peak transient, it doesn't then turn down the volume (at that exact time), it already controlled it before these possible transients, but the ultimate key is leaving clean power to operate seamlesly, so as to maintain plenty of headroom dynamics to still funvtion without audible artifact or compression (it's not trying to control it when it's already at the wall persay).This make any sense?

Not sure any other way to state this but it is having no more overall volume control but still have volume in relation to music dynamics as the amp functions. Not sure I can explain it any other way. If a person can't understand my explanation, then listening is the only way to understand it.

My question was this


> the amp might hit 4 or 5times rated power before the caps run low and distortion occurs.


 That doesn't seem right. In this case could you max out the amp?


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## MarkZ

RNBRAD said:


> Mark, the Wiki page also said the sonic results of the type of compressor McIntosh uses has the worst audible affects and is harsh and unpleasant with anything more than unfrequent activation. Kinda like reading through all that capacitor jargon, doesn't matter what it said, fact still remained. Thing with caps, the ability to prove it without listening was pretty easy. Audibility or inaudibility of something is hard to prove on paper. That's why hearing is believing.


You mentioned you don't have a lot of experience with compressors, so I would imagine it's hard for you to compare this circuit with others, no? You've got to keep in mind that there are lots of reasons to use compressors, so yes, a compressor with a soft knee and a finite ratio are going to be better than one with an infinite ratio. But a finite ratio isn't really applicable in _this_ application, unless you're willing to withstand a loss of output power.



> I think what's interesting is the PG activates based on reserve power of the internal capacitors. Wonder about external as well since I run those too? Not only that but it activates and deactivates in as little as 1/200 of a second (speed of circuitry) and also triggered by minute increases in distortion and not at any predertimed power level. I think the key being missed is not just the performance of just the Power Guard circuitry, but also the performance of the amplifier when combined with this feature. There's a combination of factors coming to play here and feel that no other amplifier and compressor can duplicate as far as detail in audible experience. That's why you can't hear the distortion or compression.


Well, the capacitor thing that the guy mentioned was just an example of the variation of rail voltage that accompanies the losses that you naturally find in amplifiers. What he said, in layman's terms, is that the power guard circuit -- being part of the internals of the amp -- does a pretty good job of accounting for these losses, so you're maximizing the amount of power that you have available before the power guard feature kicks in. A conventional compressor doesn't have this capability, so it would kick in sooner (presuming you set it to do that...). It's one of the great features of having a compressor _built in_ to the amp. I talked about this three pages ago.  But that doesn't address how the feature sounds, it just allows you to minimize using it a little bit.


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## MarkZ

RNBRAD said:


> I found this very interesting about compressors in general, cause I believe there are literally thousands of different units, and only a handful regarded as superior performers. I feel that the experience with compressors in this thread is actually from misuse/improper use of them or even junk. When used correctly, not just the PG, they shouldn't be audible at all. Wiki even mentions that. How ironic is that?? :laugh::laugh:


I think I've brought this up six times already in this thread, but you haven't understood it yet.  My point isn't about whether the pumping artifacts are audible (I've told you that I believe McIntosh when they say it's not). It's about under what conditions the *compression* is audible. The wikipedia entry might use the term "inaudible" to describe artifacts (or "side effects"), but the whole damned point of the wikipedia article was to address how compressors are used. Specifically, for _dynamic range compression_ (the title of the wikipedia entry was "dynamic range compression"!!!).

So, no, the wikipedia entry doesn't say what you think it does.

How much experience do you have with music production? Because the quote you provided is talking about that. You're a big "experience" guy, right? You lack the context to understand any of that.


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## MarkZ

RNBRAD said:


> Josh, thanks for your input and opinion. I honestly see where your coming from and totally understand it. I think we want to put this amp/compressor system under very set parameters and then contemplate as to whether it would be audible then. I still don't think so. Reason why is because even though the PG is activated the Mcintosh amp is not out of power, its not stopping the peak transients, and possibly far from it.


Actually, that's _exactly_ what it's doing. It's reducing the gain of the "peak transients". You even acknowledged that earlier. Wtf?? 



> You reach a point, the volume increase is done, but at the point it is still dynamic as if the volume was set to halfway of any other amp.


No. That's not what it's doing at all. You really don't understand how power guard works.  It's not a non-causal circuit. So it doesn't do what you think it does. You just described foobar2000's replaygain feature, which _normalizes_ rather than compresses because it's seeking ahead through the whole song to identify the peak. You can't do that with an analog circuit unless you're willing to live with a whole song's worth of lag. [oops, I used that sentence already in this thread]

You said earlier you didn't know exactly how power guard worked. Just stick with the subjective reviews of it. That's not an insult. That's a plea for you to stop attempting to provide mechanistic explanations of this circuit. It's not doing what you think it's doing.


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## RNBRAD

This is your basic take Mark, that compression regardless of circumstance is audible. 



> Of course it's audible. There's no free lunch. You try to get 200w out of a 100w McIntosh amp, powerguard will prevent it from clipping, making it sound better* than a normal 100w amp under the same conditions, but it cannot prevent the dynamics compression that accompanies these circuits. The 200w amp will still sound better.
> 
> It's not that the McIntosh circuit is inaudible -- it's that it trades distortion for compression. This is a pretty good strategy, IMO (although I'd probably prefer to have some control over attack/decay...). But it's still inferior to not clipping at all.
> 
> Volume output", in this context, refers to a change in volume of a dynamic signal. As McIntosh clearly explains, their circuit operates like all other brick wall limiters -- it kicks in when the output exceeds a threshold, and kicks off when it doesn't. The end result is dynamic range compression


I see the theme here. But continue.


Quote from link above

"I respond that if they were using compression properly, the audience would actually hear their dynamics even better, that in fact compression is a tool not for killing dynamics (unless you want it to) but for making dynamics even more articulate and audible." (Cyrus J. Aduska)

This the audible you mean mark? Maybe it's just perfect circumstance. But he also said this.

"But most of the time the correct setting of a compressor is found when you can't hear it working"
Mark, is it even possible to compress audio and do it inaudibly? Cause you've always said it's audible, at least in regards to the function of compression and the power guard, see above!! But this guy says with the correct setting you can't hear it working. Think the PG could exhibit that? Of course not you said it's audible above.



> Actually, that's exactly what it's doing. It's reducing the gain of the "peak transients". You even acknowledged that earlier. Wtf??


What are you saying here? Are you saying the PG only attenuates the "peak transients"? Like clipping off the top only or limiting the top or peak only? That would have compression written all over it. Or is it attenuating the input at all frequencies linearly? You know, kind of like a volume control.


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## Hanatsu

9 pages and counting... xD


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## MarkZ

RNBRAD said:


> This is your basic take Mark, that compression regardless of circumstance is audible.
> 
> 
> 
> I see the theme here. But continue.
> 
> 
> Quote from link above
> 
> "I respond that if they were using compression properly, the audience would actually hear their dynamics even better, that in fact compression is a tool not for killing dynamics (unless you want it to) but for making dynamics even more articulate and audible." (Cyrus J. Aduska)


You mean, they'd hear a *difference*? It has an impact on sound? It's not _inaudible_??

That is, after all, the point of using a compressor 99% of the time. Guitar players know this. Vocalists know this. Drummers _definitely_ know this. There is such a thing as too dynamic, so sound engineers use a compressor to shape the sound to be less dynamic. But the key is to do this without introducing audible pumping artifacts and without altering the high frequency response. You can achieve this by tailoring the attack, release, ratio, and knee to your goals. In the end, hopefully you have a CD that's done correctly (usually, people complain of too much compression rather than too little...).

The quote you provide above is clearly referring to music production. His assertion that it "improves" dynamics makes sense when you view it within the context of production, because you're usually using both a compressor and noise gate. So what you were throwing out before, is no longer being thrown out when you use the compressor in production. Not relevant here, because we don't use noise gates.



> This the audible you mean mark? Maybe it's just perfect circumstance. But he also said this.
> 
> "But most of the time the correct setting of a compressor is found when you can't hear it working"


"Can't hear it working" = no artifacts/"side effects". That's what people strive for in music production. 




> What are you saying here? Are you saying the PG only attenuates the "peak transients"? Like clipping off the top only or limiting the top or peak only? That would have compression written all over it. Or is it attenuating the input at all frequencies linearly? You know, kind of like a volume control.


Both. Here's how it works in really _simple_ layman's terms. It finds a "peak". When that peak lasts for at least X seconds, it triggers the compressor. It knocks down that peak by a factor of Y with a "volume control" (VCA) for Z seconds before returning to the original gain.

Glossary:

X = "attack" (powerguard = 50 - 100us, conventional compressors = adjustable)
Y = "ratio" (powerguard = infinity, conventional compressors = adjustable)
Z = "release" (powerguard = 100ms, conventional compressors = adjustable)


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## RNBRAD

He's talking about live music, so it is relevant, not compression on the recording end, but rather the affect of compressors have for the listening audience. Basically stating the effect when done correctly should be seamless, transparent and inaudible for the listeners. Sounds like this guy thinks that when a compressor is used properly, you actually can have your free lunch. Cause before you said this was achieving the impossible. 

I don't want to denote in any fashion that dynamic range compression and the use of compressors doesn't affect sound, that's its job, that's what it does, but big BUT here is can you identify it, can you hear it working? I'm betting in most cases you probably can, but this isn't "most" cases. Can you identify the amp clipping and the dynamic compression of the transients of a Mcintosh amp, particularly with Power Guard? That's the entire discussion. Can you hear it when its turned on in real time listening to real music even uncompressed 24bit music? When the PG is clearly doing its job, can you tell? Can you idenify it audibly? No doubt it's using compression and attenuation. Can you identify its dynamic range compression signature? Our entire argument is based on that single sole principle. It's not too much unlike RC's amp challenge.

Or even arguing the dynamic range compression of a 16 bit cd versus 24bit DVD/SACD. In double blinds tests show people can't audibly tell the difference. So how audible is it, really? especially when done correctly? You had me thinking this was a one in a million scenario here, McIntosh achieving the impossible. I find out, that's how it's suppose to work "inaudibly". I think it would have to be pretty bad and not the subtle differences based on our discussion. If you would of just said "Brad when done correctly with high quality compressors, they can work without hearing them." We'd of been done!!! *Anyway Mark, if you still think the PG's dynamic range compression is audibly identifiable, we are going to just have to agree to disagree*

Edit: another thing that's interesting, is the PPS document McIntosh sent me. It has a test signal 0db, overdriven signal at +14db and Mcintosh amplifier with powerguard overdriven by 14db. I'd honestly have to lay the RTA graph over each other to actually see the DB changes between the test signal and PG signal. Can't hardly see it visually on an RTA curve I'm seriously doubting you can hear it. I'm more than happy to send it to anyone that wants it, just PM me.


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## fischman

My take on compression in SQ reproduction is that it's just another tradeoff. When music is produced, either live or for recording, the audio engineer has a specific goal of what they want the listener to hear. Just as we prefer as little distortion produced by our equipment in reproduction, an audio engineer may actually introduce distortion into the music to create a specific sound. A great example is electric guitars that add distortion to create the sound desired. However, when creating an audio reproduction system, such as in your car or in your home, you do not want to add any of your own distortion, compression, etc to the recording. But as said before, there are always tradeoffs. In the case of PG you are making a tradeoff for some level of distortion, that may or may not be audible for some level of compression that may or may not be audible. Distortion, often times is easier to notice because it can sound bad, where as compression is harder to recognize unless you know what the track should sound like before hand. I would bet if you could a/b test this with a system that could play at 90db rms with peaks up to 110db with no compression, vs a system that starts using compression at 90db, you would notice the lack of dynamic sound. 

Going back the the Tube amp that replaced the Mcintosh amp earlier in the thread, it is very likely that both amps were underrated. The Mcintosh putting out 144 watts with much lower peaks due to compression vs the Tube amp that could have been putting out well over 200 watts with no compression on the peaks. Sure, distortion levels may have been slightly higher on those peaks than what would have been seen on the Mcintosh, but if they were still below a certain level they may have been inaudible. And even if they were audible, some people actually prefer a little distortion, especially in the lower mid bass/bass regions. All of this could have led to the result that was experienced with the cheaper amp outperforming, in the users opinion, the Mcintosh. It was a tradeoff of higher distortion levels for higher power level/peaks(dynamics) vs lower distortion levels with lower power level/peaks(dynamics).

BTW, RNBRAD, I think you are giving the circuit too much credit for what it is capable of doing based on physics. It is a relatively dumb circuit. It is not smart enough to analyze the full song and then provide a base line that would not actually compress any of the music. If a song averaged a swing of +/- 5db, and the song is played at a level 3db below the poing PG kicks in, you are going to experience some compression, but it may not be audible. However if there was a sudden peak of 10db, and you could compare the song on another system with the ability to provide the 10db peak, you would hear the difference. In other words it would be audible, it might not sound bad, but it would sound different and would not be accurate to the original recording.

Josh


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## RNBRAD

Good points but I'm not giving the circuit any credit accept my experience with the circuit and McIntosh's claim. For all I know it may not be "just" the circuit. I can only describe my experience with it and the amp. According to my experience and reviews of these types of circuits, they should provide exactly what I've experienced. That is when implemented properly. I just don't think this circuit is compressing in that "audible" range. Like the guy stated in the link,


> Extreme compression can be useful and cool-sounding in some specialized circumstances; but the vast majority of the time you'd actually benefit most from a transparent "invisible hand" keeping your levels under control without messing things up. And that requires lighter settings. If there will be any tonal improvements from the compressor, expect them to be very subtle.


 So this is a clue at how a compressor needs to be implemented, probably no matter the scenario, or it gets into the nasty & audible range. He also talks about those as well. Certain compressors provide exactly that, distorted compressed sound. I'm betting tho, the PG works in that transparent subtle range, thus confirming my experience.

But like I said before, don't put it in a box, like send a pink noise signal to it, run it to clipping then a-b it with the switch on and off listening for subtle changes. That's not reality. Play some dynamic music your very familiar with and just play it at max volume, see if it sounds compressed or if it sound just as dynamic and clear at max as it did at 1/2 volume. Though the posted review ealier, the amp probably was not pegged, but the guy also stated other amps at that volume sound compressed and he did not notice that with the McIntosh. That was his experience, but can't verify all the parameters of his listening experience. I say good luck even making a Mc amp sound compressed with normal music at any volume.


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## MarkZ

RNBRAD said:


> Edit: another thing that's interesting, is the PPS document McIntosh sent me. It has a test signal 0db, overdriven signal at +14db and Mcintosh amplifier with powerguard overdriven by 14db. I'd honestly have to lay the RTA graph over each other to actually see the DB changes between the test signal and PG signal. Can't hardly see it visually on an RTA curve I'm seriously doubting you can hear it. I'm more than happy to send it to anyone that wants it, just PM me.


Yeah, could you send it my way? Because I have no idea what you're talking about. Why would you use an RTA to illustrate something that has to do with dynamics? It averages over time.  He might have been addressing the high frequency issue, which is common with compressors, not the dynamic range issue.


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## masswork

Same question with Mark 
And yes please, RNBRAD, can you send me the file too?

To date i never saw power guard light turn on. Maybe i set the gain safe enough to keep the PG inactive. 
Why would we want to overdrive the amp btw?


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## RNBRAD

PM me your emails where or how you want it sent.


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## Golden Ears

It has been said that a tube amp overdriven will often sound less distorted than a similar wattage solid state amp because of the differences in sound of perceived distortion of even vs odd order distortion.

In this regard, my home Tube amp an Audio Research VS -110 with great northern sound upgraded capacitors as well as a few other things, can sound nearly as loud as. Bryston 4b 200 W.p.c. Solid state amp. Drums in particular tend to overload nicely in tube gear as opposed to solid state.


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## feeshta

Wow, I really stirred up a hornets nest with that post. Sorry I have been inactive for a little while. Was away for the holidays.

To clear up a few things, in my experience, Power Guard is most definately audible under certain circumstances. Those circumstances were when I first purchased the amplifier. I used it to power a Boston Acoustics 6.5 component set, and a single JL 12w3. The system would sound fine up to a certain volume, them the sub would simply "run out of gas" and fail to keep up with the front stage dynamically. This was because the amp couldn't provide any more clean output, and the inefficiency of the subwoofer compared to the front stage became very apparent. I solved this problem by adding an MMATS amplifier for the sub, and going bi-amped on the front stage with the McIntosh. 

After I did this, The McIntosh almost never strayed into the realm where powerguard would activate, even at rather extreme listening levels. 99% of the time the PG light would not activate at all, only on the rare occasion that I set out to intentionally test the limits of the system's output would it ever activate, and this was true for the setup later on when the MB Quarts replaced the Bostons after one of the Bostons chewed up a wire lead and stopped working. 

The difference between these two amps was readily apparrent at the levels I typically listened. Basically, the US Amps made you feel like it was working with less weight. It just sounded more powerful. 

I wish I had bench tested the TU-600, because it makes me curious. I know the McIntosh was capable of 570 or so watts cleanly with all channels driven. The US Amps was rated at only 300 in the amplication it was installed in. Being under-rated is one thing, but for it to have enough power above and beyond the McIntosh to create this much of a difference seems a bit dubious.


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## RNBRAD

Yes, there comes a point they won't provide any more volume. What amp were you using?


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## Golden Ears

Tubes amplifiers have a full bodied sound and can reproduce more. Midrange and lower midrange info below about 250hz solid state tends to deliver cleaner and more impactful
Bass. Too bad you sold the Mcintosh because it would have been a great amp to handle your midd bass and bass.


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## feeshta

RNBRAD said:


> Yes, there comes a point they won't provide any more volume. What amp were you using?


It was an MC-431. The fact that McIntosh halves the rail voltage in a bridged situation didn't help in that situation as you don't get the normal jump in power from bridging. 



Golden Ears said:


> Tubes amplifiers have a full bodied sound and can reproduce more. Midrange and lower midrange info below about 250hz solid state tends to deliver cleaner and more impactful
> Bass. Too bad you sold the Mcintosh because it would have been a great amp to handle your midd bass and bass.


I think you may have misread what I originally posted. The US Amps absolutely kicked the crap out of the McIntosh, ESPECIALLY in the mid-bass. More authoritative, impactful, and just plain more powerful. Also, what am I going to do with a 4x100 Watt mid-bass amp the size of briefcase? The reason I made the switch in the first place was due to lack of space. 



cajunner said:


> higher distortion makes the sound "perceptually" louder, that's where you were getting the difference in output indication, or observations.


Give me a little credit here man, I know what distortion sounds like. I am not a moron. 20 plus years of listening to my brother playing with distortion pedals on his guitar and tweaking settings with him in his home studio looking for new sounds has taught me plenty about what distortion is and how it sounds. If it's distortion, it's kick-ass magical distortion that should be bottled and sold worldwide.


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## putergod

I'm going to repeat myself...
I own SEVERAL US Amps amplifiers. Every one of them puts out ALMOST DOUBLE what it's rated it (measuring using an o-scope and DMM).
It seemed louder because...

...wait for it...

...it WAS louder. The US Amps amplifier was a more powerful amplifer - regardless of ratings.


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## RNBRAD

feeshta said:


> I think you may have misread what I originally posted. The US Amps absolutely kicked the crap out of the McIntosh, ESPECIALLY in the mid-bass. More authoritative, impactful, and just plain more powerful. Also, what am I going to do with a 4x100 Watt mid-bass amp the size of briefcase? The reason I made the switch in the first place was due to lack of space.


This comment is really interesting to me. Your running a good clean 200 watts to a set of Boston Acoustic 6.5'' component set and having what seems like a 25watt (2 x 12.5) amp experience. You should be able to run that set with 200 plus watts into oblivion and smoke them like a cheap Mexican cigar!!!! I run the exact same power but not to just a 6.5'' 3 ways set but also to another 6 speakers with a 2x100 watt McIntosh amp. I can't run this amp to the end of the rope without my ears ringing in pain. My midbass kick like subs. I couldn't ask for a better performing midbass and no way do I think it's possible even with a 1000 watt amp. My speakers would be toast. Anyway, something isn't exactly right here but not sure what it is. A key component is missing. If it was a PG issue, that's easily defeated by a switch then it will sound distorted like any other amp. That amp should easily put out 200 watts per side before the PG is ever activated and you can't get some 6.5's to perform with that kind of power? Sometings not right here, maybe x/o, freq boost, something. No offense, but really. Just doesn't make a lick of sense.


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## feeshta

putergod said:


> I'm going to repeat myself...
> I own SEVERAL US Amps amplifiers. Every one of them puts out ALMOST DOUBLE what it's rated it (measuring using an o-scope and DMM).
> It seemed louder because...
> 
> ...wait for it...
> 
> ...it WAS louder. The US Amps amplifier was a more powerful amplifer - regardless of ratings.


It would have to be well over double the rated output. I know for a fact the McIntosh threw down 580 or so clean watts, which is almost dead on double the rated power output of the TU-600. You would have to exceed that pretty significantly to produce the results heard. couple that with the fact that I never pushed the McIntosh or the TU- 600 to their actual limits when listening to music and you will see why I don't believe it was just louder. 



RNBRAD said:


> This comment is really interesting to me. Your running a good clean 200 watts to a set of Boston Acoustic 6.5'' component set and having what seems like a 25watt (2 x 12.5) amp experience. You should be able to run that set with 200 plus watts into oblivion and smoke them like a cheap Mexican cigar!!!! I run the exact same power but not to just a 6.5'' 3 ways set but also to another 6 speakers with a 2x100 watt McIntosh amp. I can't run this amp to the end of the rope without my ears ringing in pain. My midbass kick like subs. I couldn't ask for a better performing midbass and no way do I think it's possible even with a 1000 watt amp. My speakers would be toast. Anyway, something isn't exactly right here but not sure what it is. A key component is missing. If it was a PG issue, that's easily defeated by a switch then it will sound distorted like any other amp. That amp should easily put out 200 watts per side before the PG is ever activated and you can't get some 6.5's to perform with that kind of power? Sometings not right here, maybe x/o, freq boost, something. No offense, but really. Just doesn't make a lick of sense.


To be clear, the McIntosh did toast that Boston set after I got a seperate sub-amp and went biamped with all 4 channels into the 6.5 set. It melted the solder on one of the voice coil leads and that was the end of the Bostons. They lasted about 2 years or so, maybe a little less, which lead me to purchase the MB Quart Q's. The Q's handled the McIntosh fine for about 2 years before I switched out to the TU-600 and were eventually replaced without having failed. 

If you would have asked me about the McIntosh the day before I installed the TU-600, I would have told you it was the most kick-ass amplifier I had ever experienced. I know it was putting out 144 watts per channel because I had the thing bench tested. I was sad to see it go. I loved that thing. 

It wasn't output that is the real defining difference between these two amps, I wasn't using either of them to 100% of their potential power output under normal circumstances. Both of them would play well louder than I would normally listen to music, and I listen pretty loud. The difference was that at higher listening levels, anything past about 75% of the max volume I would normally listen, the TU-600 sounded cleaner, more authoritative, much more aggressive and dynamic in the attack of transients. That sense of power-compression was completely absent. 

Also, the TU-600 has absolutely zero processing, and the McIntosh's processing had been bypassed. The only "processing" was coming from the crossovers that came with the MB Quarts and the built in crossover and time alignment in the headunit, which stayed set the same minus the loss of the ability to independantly time-align each driver. The headunit had an eq, but I left it set flat because I never had time to properly set it up until a few months after the switchover. I had only had the HU for about 3 weeks when the switch was made. 

I understand your scepticism completely. I was blown away by the difference myself, and would be right there in your shoes if it had not happened to me and this was someone else telling the story.


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## Golden Ears

Well it sounds like the US amps is just a better amplifier all around.

In Home hi-end audio there can be system synergy of components. Some speakers perform magic with certain amplifiers. Like I have some Infinity Reference Standard RS1-b (the little brother to the Infinity IRS) these planar magnetic drivers and polypro midwoofers sound great with solid state amplifiers that deliver tons of current- )IMHO more air- detail, speed AND MIDRANGE float- tube amps fail to drive them with authority (just provide too much warmth and midrange bloat)I also have Chapman T-9 MKII's which have traditional Dynamic cones from Europe, which sound best with tubes in all respects- hghs, lows, and midrange.

There may be some cable synergy as well.

Once in awhile people stumble (in rare cases design) entire systems that sound great on the first try with near perfect synergy. I have no idea if it is related to impedance matching, driver dispersion, slew rates..whatever... just like a good chef can take a few ingredients and whip up a masterpiece- whereas the sous chef- even with nearly as many years of training, just can't do the dish right with the same ingredients and same kitchen.

This synergy also transfers to the transfer function of your car. I remember hearings what I expected to sound like garbage sounding good ... Bose 901 (tons of EQ in their module) + Sony crap solid state amp (zero EQ) , in a larger room with tons of hard surfaces, and a mediocre looking Hitachi tape declk. In Frank Loessers (Writer of guys and Dolls and other musicals) in the Hamptons and was just perplexed that these componets audiotioned separately many times and always before sounding like crap, sounded good. Yes there was detail missing, but the overall delivery was still far better than what you would hear from any mid-fi system.

it sounds to me that the US amps are just plain better amps ...or you stumbled onto some great synergy (less likely).

Dynamic geadroom (peak power) might be very high with your US amps. The McIntosh amplifers aren't really anything amazing in the home arena just plain solid amps- most people would say they are glorified mid-fi in terms of their sound but with lots of power and current delivery behind them- along with reliability. In home Hi-Fi I would never spend the money for a McIntosh solid state amplifer (other than the 500 watt monoblock- whih is OK and somehow has sounded sweeter than others in demos).

Pass Labs for instance has fewer gain stages in some of their amps- which are for the most part bridged as well. Some say fewer gain stages give it is character.

I owned Bryston 4b amplifers for nearly 20 years in various iterations, and none of them sounded the same. I decided to try out the 1000 watt Bryston 10b's and found that for some reason, the Bryston 4b's sounded far better (clearer- more tonally accurate, less congested and constricted and I was not running them anywhere near 1/4 power). 

To many from Pro audio backgrounds , Current is current.... an amp is an amp. 

To some a grape is a grape. And top rated wines are not worth the money (I happen to not care much for wine, and would fall into this category not appreciating much over say $40 retail a bottle). I understand there are layered flavors, nuances, in more expensive wines, but it doesn't capture my interest.

The vast majority of amplifers sound the same. This is true of nearly all lower hi-fi and mid fi and of say 80-90 percent of Hi-end. A few amplifiers- do stand out ..and SIGNIFICANTLY stand out. I heard the Bob Carver (yes..oddly Carver...I must be destroying credibility using Bose and Carver in the same post) 305 Tuibe monoblock Black Beauty amplifers ..simple Class A/B ..but with some odd telvision derived circuit... that just were incredbile..like ridiculously incredible. Air- depth without limits, layering front to back, image definiton, dynamic, and oh so REAL sounding.. it was scary. But there was some synergy, because they did nto sound amazing playing through $65,000 Magico Q7's..they sounded amazing through a set of $9000 speakers- but was simply one of the most accurate reproductions of a musical performance I have ever heard. I bought those speakers- and they are great, but need the entire system to sound their best (and yes I know how much the room acoustic factors in... the place I heard them was NOT A GOOD ROOM- and the Carvers somehow deal with that with this circuit that seems to remove the room nastiness from teh equation). Also I have never liked the sound of any other Carver product. Certainly not enough to buy them- but these are totally different.

I do think amplifers have character, and not only at clipping, I also would probably fail Richard Clarks Challenge as I don't think I could identify anything accurately (wine women or song) unless there were grosss differences in 24 trials without getting impatient and making a mistake.


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## Hanatsu

Wall of text crashed my phone...

Sent from my Samsung Galaxy 3 via Tapatalk.


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## feeshta

I have never before heard any differences between amplifiers. I don't really listen to much high end home audio stuff,my B&W DM-302's and Paradigm 12 have been fine for me for years now in that respect. I simply don't listen much in the home, and use them more for home theater. 

I don't really hear any appreciable difference in imaging and staging to be honest, just in the character of the sound delivered. Imaging and staging was never very great in that car, with either amp, as I went with factory locations for anti-theft purposes. 

I too could care less about wine, but when it comes to beer and women, well that's a different story.  I didn't come by my avatar by chance. I need to talk the old lady into holding up a Chimay Grande Reserve or Westvletterren Glass next time :laugh:


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## Hanatsu

http://www.matrixhifi.com/ENG_contenedor_ppec.htm

I find that test... amusing.

Sent from my Samsung Galaxy 3 via Tapatalk.


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## feeshta

Hanatsu said:


> http://www.matrixhifi.com/ENG_contenedor_ppec.htm
> 
> I find that test... amusing.
> 
> Sent from my Samsung Galaxy 3 via Tapatalk.


In general, I completely agree with the premise of this test. To be completely honest, the idea that an amp is an amp was a big part of why I chose to part with the McIntosh, which I loved. The reason I ended up with the US Amps was that I couldn't pass up a great deal. I went into the store intent on buying another brand, but when I got talking to the lead installer he offered me a deal I couldn't pass up(dealer cost) and curiousity got the better of me. I paid $430 for the US Amps. 

Incidentally, I ended up with the McIntosh for similar reasons. I went to the shop to buy two soundstreams for a total of $800, and they had the McIntosh up on the wall marked at $1200. I asked about it just because I was curious. I had not intention of buying it, but the store owner ended up offering to sell it to me for the same $800 I was going to pay for the Soundstreams, and I happily took it. I guess I was the first person to ask about it in the couple months it had been there, and they were finding that they just didn't have a market for McIntosh in rural Maryland. My cousin was insanely jealous when I came home with that thing, as he had just recently bought the same Soundstreams I intended to buy. :laugh:


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## RNBRAD

Not sure why people experience some of the things they do. Not doubting anyone's experience but try to understand the picture and maybe some variables not in the details that could shed some light as to why it was experienced the way it was.

This is my take on the differences experienced between the amps. IMHO it is 1 of 2 things. It's either disortion related or power related. Now distortion doesn't necessarily mean amp distortion alone. You take a more powerful amp and it can create *"more*" audible distortion from your speakers, and as Cajunner said, this is mostly desired. This is more true than most here realize and many will deny it but it has been proven many many times. Velodyne is a perfect example as this is why they discontinued their servo car line. The market per se didn't like the sound of them, too clean!!! Many people have become accustomed to distortions at certain frequency ranges at certain volumes. I think many confuse a coloured versus dynamic experience, it can be very deceiving. I'm not saying this is happening, but I'm also not saying it either. It's not always a bad thing, depends on perception, distortion can and has proven to be very pleasing to the ear. I think our experiences are really just different levels of distortion in our music. We have an entire vocabulary to express the differences in distortion, add yours here______ Cause really, all things being equal, bias' excluded. These amps sound the same unless we are operating in the distortion/clipping range of the amp and we take into account the distortion ranges of our speakers. Most of the discussion on amp differences in this forum are the differences between amps in the "*inaudible*" range of human hearing. I'm sure there are many nay sayers on RC's amp challenge, but I don't see any of them taking his money either. One thing we have to realize though, is many of us like music in the audible distortion range. We just don't like the use of that word ya know, it denotes a lesser quality or a bad connotation of the sound of music. If we could manufacture a system that produced absolutely no distortion, I bet most of you wouldn't like it as much as your distorted music. It's all in what your use to.


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## LovesMusic

Distortion definitely is precieved louder in most aspects of audio...

Plug into my cheap roland cube 30x solid state amp and youll see volume at the amp is at about a 1/4 high while Gain is at 3/4 high... volume pot on the guitar at a 3 or 4 any louder id pop the speaker.... only way to get that crunch i like.. 

Pleasant distortion is all about overdriving the amp...least it is for me =)


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## feeshta

RNBRAD said:


> Not sure why people experience some of the things they do. Not doubting anyone's experience but try to understand the picture and maybe some variables not in the details that could shed some light as to why it was experienced the way it was.
> 
> This is my take on the differences experienced between the amps. IMHO it is 1 of 2 things. It's either disortion related or power related. Now distortion doesn't necessarily mean amp distortion alone. You take a more powerful amp and it can create *"more*" audible distortion from your speakers, and as Cajunner said, this is mostly desired. This is more true than most here realize and many will deny it but it has been proven many many times. Velodyne is a perfect example as this is why they discontinued their servo car line. The market per se didn't like the sound of them, too clean!!! Many people have become accustomed to distortions at certain frequency ranges at certain volumes. I think many confuse a coloured versus dynamic experience, it can be very deceiving. I'm not saying this is happening, but I'm also not saying it either. It's not always a bad thing, depends on perception, distortion can and has proven to be very pleasing to the ear. I think our experiences are really just different levels of distortion in our music. We have an entire vocabulary to express the differences in distortion, add yours here______ Cause really, all things being equal, bias' excluded. These amps sound the same unless we are operating in the distortion/clipping range of the amp and we take into account the distortion ranges of our speakers. Most of the discussion on amp differences in this forum are the differences between amps in the "*inaudible*" range of human hearing. I'm sure there are many nay sayers on RC's amp challenge, but I don't see any of them taking his money either. One thing we have to realize though, is many of us like music in the audible distortion range. We just don't like the use of that word ya know, it denotes a lesser quality or a bad connotation of the sound of music. If we could manufacture a system that produced absolutely no distortion, I bet most of you wouldn't like it as much as your distorted music. It's all in what your use to.


There are plenty of studies focused on data extracted from comparing the electrical output of amplifiers, and when you keep things inside the envelope of distortion, of course the results will be identical. If it were not, there would be real issues.

I personally would like to see someone do study based on the actual end behavior of the speaker itself, rather than the electrical output signal of the amplifier. Because in the end, the ability of the amplifier to force a speaker to do what is intended is the ultimate test of the amplifier. 

I suspect you would see faster cone acceleration, and lower deviation from the ideal from the TU-600, even if the two amplifiers were calibrated to have exactly the same RMS output from a given input signal.


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## feeshta

Also, in response to the part about Velodyne, they simply don't provide enough output. I once compared a home theater sub from them, and output was ridiculously low for the price point. And that wasn't just perception. 

You have to keep in mind that music is recorded and processed to sound correct on the average speaker system. If the velodyne was the norm, music would be produced much differently, and the Velodyne would sound correct. As it is now, it is actually the velodyne system that sounds incorrect, because the original recording has been modified in a way that makes it sound more accurate when played through a conventional loudspeaker. People don't like the Velodyne sound because it sounds wrong, and in actuality, it IS wrong. It simply doesn't sound like the original instrument does. It's just like the fact that a flat RTA curve sounds awful because the mix wasn't aimed at a sytem with a flat RTA curve. Same deal. 

With a recording made to take advantage of the Velodyne's precision, and mixed to be played on a system with a flat RTA curve, you could achieve really great sound. But the reality is that the VAST majority of recordings are processed in a way that ends up making those features actually undesirable. Some gear-head snobs will insist that the Velodyne is really better, but it just plain isn't in the real world.


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## RNBRAD

feeshta said:


> Also, in response to the part about Velodyne, they simply don't provide enough output. I once compared a home theater sub from them, and output was ridiculously low for the price point. And that wasn't just perception.
> 
> You have to keep in mind that music is recorded and processed to sound correct on the average speaker system. If the velodyne was the norm, music would be produced much differently, and the Velodyne would sound correct. As it is now, it is actually the velodyne system that sounds incorrect, because the original recording has been modified in a way that makes it sound more accurate when played through a conventional loudspeaker. People don't like the Velodyne sound because it sounds wrong, and in actuality, it IS wrong. It simply doesn't sound like the original instrument does. It's just like the fact that a flat RTA curve sounds awful because the mix wasn't aimed at a sytem with a flat RTA curve. Same deal.
> 
> With a recording made to take advantage of the Velodyne's precision, and mixed to be played on a system with a flat RTA curve, you could achieve really great sound. But the reality is that the VAST majority of recordings are processed in a way that ends up making those features actually undesirable. Some gear-head snobs will insist that the Velodyne is really better, but it just plain isn't in the real world.


Well a Velodyne is somewhat of a purists sub, they are not going to have compressed and adultered source material. The Velodyne doesn't sound wrong with appropriate material and equipment, arguably the most accurate and least distorted subwoofer ever made for home and car audio. They just don't have that "hit' per se, that extra 20-30% distortion from a typical sub that increases volume output magnitudes louder and what you and I have become acustomed to. That's what your missing. It's not that the subs are inacurate. We have come to the point where good sound is bad and bad sound is good. If you listen to a top SQ car like Scott Buwalda's, I think you would be surprised, it would probably sound real close to those velo's. Heck he may use them. I know what your talking about though, I'm not fond of Velo's myself for the exact reasons you stated as well as many other high end low distortion subs. Like I said earlier, distortion in certain instances, especially with a sub, can sound very appealing. A typical Velo sub has 20 to 30x less distortion at typical listening volumes than the markets average subwoofer. Can you even imagine, well you dont have to cause you experienced it, but how a sub so clean can change the sound that much? Can you say we love distortion? We do!!!!!


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## putergod

Velodyne is my most favorite sub ever! And I'm not being sarcastic...


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## feeshta

RNBRAD said:


> Well a Velodyne is somewhat of a purists sub, they are not going to have compressed and adultered source material. The Velodyne doesn't sound wrong with appropriate material and equipment, arguably the most accurate and least distorted subwoofer ever made for home and car audio. They just don't have that "hit' per se, that extra 20-30% distortion from a typical sub that increases volume output magnitudes louder and what you and I have become acustomed to. That's what your missing. It's not that the subs are inacurate. We have come to the point where good sound is bad and bad sound is good. If you listen to a top SQ car like Scott Buwalda's, I think you would be surprised, it would probably sound real close to those velo's. Heck he may use them. I know what your talking about though, I'm not fond of Velo's myself for the exact reasons you stated as well as many other high end low distortion subs. Like I said earlier, distortion in certain instances, especially with a sub, can sound very appealing. A typical Velo sub has 20 to 30x less distortion at typical listening volumes than the markets average subwoofer. Can you even imagine, well you dont have to cause you experienced it, but how a sub so clean can change the sound that much? Can you say we love distortion? We do!!!!!


It seems like you missed the point a little here. The Velodynes don't have that "hit" because it was intentionally engineered out of the original recording in order to make normal sub-woofers sound more accurate. That makes the velodynes unnaturally subdued, and it is not accurate sound reproduction. It is accurate _signal_ reproduction, but nothing like listening to the instrument live. A live kick-drum has that "hit" by it's nature. A reproduction of it's sound that does not include this is, by definition, inaccurate. 

It's not Velodyne's fault that this is true, but calling the Velodyne the most accurate sounding subwoofers out there is simply false. To make a Velodyne sub sound correct, you would need to completely remaster the recording without any normalization or compression. 

The fact that some people regard the sound of the Velodyne as correct is a trick of the mind. Your brain knows that this sub is designed to eliminate distortion, and therefore you assume that you were incorrect in your previous observations. You weren't. The Velodyne really does sound like crap. It's just really really clean and accurate crap.


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## MarkZ

feeshta said:


> There are plenty of studies focused on data extracted from comparing the electrical output of amplifiers, and when you keep things inside the envelope of distortion, of course the results will be identical. If it were not, there would be real issues.
> 
> I personally would like to see someone do study based on the actual end behavior of the speaker itself, rather than the electrical output signal of the amplifier. Because in the end, the ability of the amplifier to force a speaker to do what is intended is the ultimate test of the amplifier.
> 
> I suspect you would see faster cone acceleration, and lower deviation from the ideal from the TU-600, even if the two amplifiers were calibrated to have exactly the same RMS output from a given input signal.


That test was done about thirty years ago by David Hafler, IIRC.

But, as always, measurements will describe what you're talking about. "Faster cone acceleration" = frequency response (and failure to achieve the dictated freq resp will result in harmonic distortion). "Lower deviation" also refers to a distortion measure, if I'm understanding you.


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## RNBRAD

feeshta said:


> It seems like you missed the point a little here. The Velodynes don't have that "hit" because it was intentionally engineered out of the original recording in order to make normal sub-woofers sound more accurate. That makes the velodynes unnaturally subdued, and it is not accurate sound reproduction. It is accurate _signal_ reproduction, but nothing like listening to the instrument live. A live kick-drum has that "hit" by it's nature. A reproduction of it's sound that does not include this is, by definition, inaccurate.
> 
> It's not Velodyne's fault that this is true, but calling the Velodyne the most accurate sounding subwoofers out there is simply false. To make a Velodyne sub sound correct, you would need to completely remaster the recording without any normalization or compression.
> 
> The fact that some people regard the sound of the Velodyne as correct is a trick of the mind. Your brain knows that this sub is designed to eliminate distortion, and therefore you assume that you were incorrect in your previous observations. You weren't. The Velodyne really does sound like crap. It's just really really clean and accurate crap.


No I totally understand you. Read the 1st two lines in my last paragraph again. I'm talking unadultered source material. Most or many purists listen to 24bit masters as well as vinyl. Purists control every aspect or variable in the reproduction phase to make sure the final signal is as close to the actual production as possible. Clean and Accurate crap, that was funny!!:laugh::laugh:


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## feeshta

MarkZ said:


> That test was done about thirty years ago by David Hafler, IIRC.
> 
> But, as always, measurements will describe what you're talking about. "Faster cone acceleration" = frequency response (and failure to achieve the dictated freq resp will result in harmonic distortion). "Lower deviation" also refers to a distortion measure, if I'm understanding you.


Things have actually changed a bit in the past 30 years, it would be nice to see it revisited with modern measurement techniques. I know B&W does it for loudspeakers, but they always use a reference amplifier in order to standardize results. I would like to see the same measurement techniques applied to amplifiers. The cost of doing so was once extremely prohibitive, but these days it could be done with far less cost due to the much lower cost of processing power. 

There are some things that are considered truisms in audio that mildly piss me off. Such as the Nyquist theorem. It is technically correct that you can reproduce a signal with a sampling rate that is twice as fast, provided the signal is a sign wave of course. The problem is there will be no nuance as you approach the high end of the frequency response.


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## MarkZ

feeshta said:


> Things have actually changed a bit in the past 30 years, it would be nice to see it revisited with modern measurement techniques. I know B&W does it for loudspeakers, but they always use a reference amplifier in order to standardize results. I would like to see the same measurement techniques applied to amplifiers. The cost of doing so was once extremely prohibitive, but these days it could be done with far less cost due to the much lower cost of processing power.
> 
> There are some things that are considered truisms in audio that mildly piss me off. Such as the Nyquist theorem. It is technically correct that you can reproduce a signal with a sampling rate that is twice as fast, provided the signal is a sign wave of course. The problem is there will be no nuance as you approach the high end of the frequency response.


All signals are sine waves or combinations thereof. That's why nyquist holds. If your signal is too fast for nyquist, then you'll also see that its frequency content is too high.


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## feeshta

RNBRAD said:


> No I totally understand you. Read the 1st two lines in my last paragraph again. I'm talking unadultered source material. Most or many purists listen to 24bit masters as well as vinyl. Purists control every aspect or variable in the reproduction phase to make sure the final signal is as close to the actual production as possible. Clean and Accurate crap, that was funny!!:laugh::laugh:


I see, but unless they are getting a hold of the original master and and starting from scratch, it will still not sound very good on a Velodyne. The characteristics are so different that it would require a complete remaster. Really the Velodyne would probably sound best with the original master recording, but then you would have to do something with everything other than the Sub-bass. The best application would probably be a multiple track system, like 5.1 with a dedicated sub-bass track. Then you could leave the rest of the recording mastered in the way it will sound best on normal loudspeakers. But nobody is going to go to all that trouble to accommodate one brand


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## feeshta

MarkZ said:


> All signals are sine waves or combinations thereof. That's why nyquist holds. If your signal is too fast for nyquist, then you'll also see that its frequency content is too high.


Look at an audio signal on an o-scope and tell me it's a sign wave.


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## MarkZ

feeshta said:


> Look at an audio signal on an o-scope and tell me it's a sign wave.


I said a combination of them.


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## putergod

MarkZ said:


> I said a combination of them.


^^ What he said.

It's _many_ sign waves...


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## RNBRAD

feeshta said:


> I see, but unless they are getting a hold of the original master and and starting from scratch, it will still not sound very good on a Velodyne. The characteristics are so different that it would require a complete remaster. Really the Velodyne would probably sound best with the original master recording, but then you would have to do something with everything other than the Sub-bass. The best application would probably be a multiple track system, like 5.1 with a dedicated sub-bass track. Then you could leave the rest of the recording mastered in the way it will sound best on normal loudspeakers. But nobody is going to go to all that trouble to accommodate one brand


Obviosly your experience with Velodyne subs is not the norm, but in fact just the opposite. That's why I said it was preference or taste, what your accustomed to. That's ok though cause we all have different tastes. Velodyne though have definitely won their share of awards and reviered among many in the high end home sub market and not because they sound like crap. I don't think there sound is distinct and their performance is along the lines of Pro Audio subs or "studio quality" Like Tannoy, JBL, Yamaha, Yorkville etc. Many of us expect the same distorted sound from our car subs in our home as well. It's a little easier to find in the home market and almost impossible among studio or pro audio subs. Most would not like the performance of those subs in our cars and some in the homes. I don't think it's as much compression in recording as you think. But as I stated earlier, it's all in what you are use to and expect from a sub. If you like that "kicker" sub bass sound which dominates the car audio systems of today and many homes, your not going to like the sound of the others mentioned, in your home or car. It's kind of like the McIntosh power guard. Most people probably prefer the sound of it off. I do just for subs. This allows clipping/distortion from my amp, drives my subs further into distortion which to me is appealing, but it is "Not" accurate!!! It is coloured and highly distorted sound. I think your in the same boat, you just don't realize it. Pro audio/studio subs many use in homes but even less are used in our cars. To me, it's all because of the drivers distortion output characteristics and our tastes. Like I said, we like our distorted subs better than a clean and accurate sub. I really don't think people understand how much this plays into our style of music and taste more so today than anytime in the past. Exactly why SPL is so popular. SPL is all about high levels of distortion. Now you can't even buy a sub that isn't designed for higher power and more SPL. Look at how much beefier the subs are today than say just 10 years ago. Go back 20 yrs. the magnets on the Punch 15" subs used in Mark Fukuda's blazer were about the size of a typical 6.5" to 8"" driver today. Nope not kidding!! It's literally a bass revolution what's happened over just a relatively short span in time. Our (unnatural) tastes have changed and molded an entire industry. Think about it!! Now think about why you don't like that Velodyne sub.


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## feeshta

RNBRAD said:


> Obviosly your experience with Velodyne subs is not the norm, but in fact just the opposite. That's why I said it was preference or taste, what your accustomed to. That's ok though cause we all have different tastes. Velodyne though have definitely won their share of awards and reviered among many in the high end home sub market and not because they sound like crap. I don't think there sound is distinct and their performance is along the lines of Pro Audio subs or "studio quality" Like Tannoy, JBL, Yamaha, Yorkville etc. Many of us expect the same distorted sound from our car subs in our home as well. It's a little easier to find in the home market and almost impossible among studio or pro audio subs. Most would not like the performance of those subs in our cars and some in the homes. I don't think it's as much compression in recording as you think. But as I stated earlier, it's all in what you are use to and expect from a sub. If you like that "kicker" sub bass sound which dominates the car audio systems of today and many homes, your not going to like the sound of the others mentioned, in your home or car. It's kind of like the McIntosh power guard. Most people probably prefer the sound of it off. I do just for subs. This allows clipping/distortion from my amp, drives my subs further into distortion which to me is appealing, but it is "Not" accurate!!! It is coloured and highly distorted sound. I think your in the same boat, you just don't realize it. Pro audio/studio subs many use in homes but even less are used in our cars. To me, it's all because of the drivers distortion output characteristics and our tastes. Like I said, we like our distorted subs better than a clean and accurate sub. I really don't think people understand how much this plays into our style of music and taste more so today than anytime in the past. Exactly why SPL is so popular. SPL is all about high levels of distortion. Now you can't even buy a sub that isn't designed for higher power and more SPL. Look at how much beefier the subs are today than say just 10 years ago. Go back 20 yrs. the magnets on the Punch 15" subs used in Mark Fukuda's blazer were about the size of a typical 6.5" to 8"" driver today. Nope not kidding!! It's literally a bass revolution what's happened over just a relatively short span in time. Our (unnatural) tastes have changed and molded an entire industry. Think about it!! Now think about why you don't like that Velodyne sub.



They can win all the awards they want, they still don't sound right with a normal recording. Every person I have ever talked to about Velodyne had the same initial reaction. Not enough output. Or more accurately, "you sure the thing is on?" Some people then re-evaluate their opinions about how things are supposed to sound, because they know that the Velodyne is in point of fact more accurate. That is true, but it does not mean it sounds better. In fact it doesn't. Ask any sound engineer. 

Now, for winning a competition, they might actually be good. This is because a lot of the recordings used in competition testing are actually direct unmolested masters. This is where the Velodyne will shine. Good luck finding a recording of any good music that is recorded this way though. 

I build stereos because I love music, not because I am obsessed with technological perfection. I want the music to sound as close to real music as possible, and the bottom line is that with commercially available recordings, Velodyne subs DO NOT sound like real music. 

If you enjoy the sound of a Velodyne sub, that's your discretion, but in my opinion, 90% of people who "prefer" Velodyne are basing their opinion on perceptions of technical accuracy and NOT on the listening experience. If you did a blind listening test and without telling people that the Velodyne is technically much more advanced than another decent sub, I guarantee you the vast majority of people would prefer the other sub, and it's not because they prefer distortion.


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## RNBRAD

feeshta said:


> They can win all the awards they want, they still don't sound right with a normal recording. Every person I have ever talked to about Velodyne had the same initial reaction. Not enough output. Or more accurately, "you sure the thing is on?" Some people then re-evaluate their opinions about how things are supposed to sound, because they know that the Velodyne is in point of fact more accurate. That is true, but it does not mean it sounds better. In fact it doesn't. Ask any sound engineer.
> 
> Now, for winning a competition, they might actually be good. This is because a lot of the recordings used in competition testing are actually direct unmolested masters. This is where the Velodyne will shine. Good luck finding a recording of any good music that is recorded this way though.
> 
> I build stereos because I love music, not because I am obsessed with technological perfection. I want the music to sound as close to real music as possible, and the bottom line is that with commercially available recordings, Velodyne subs DO NOT sound like real music.
> 
> If you enjoy the sound of a Velodyne sub, that's your discretion, but in my opinion, 90% of people who "prefer" Velodyne are basing their opinion on perceptions of technical accuracy and NOT on the listening experience. If you did a blind listening test and without telling people that the Velodyne is technically much more advanced than another decent sub, I guarantee you the vast majority of people would prefer the other sub, and it's not because they prefer distortion.


I think we are on the same page, minus one thing and that's the colour and distortion aspect. If the subs you listen to and 'like" were as accurate as the Velodyne, you couldn't like it based on your statements, because they would more accurately reproduce the so called bad recordings. So if those subs you like are "not" accurate enough to reproduce this, what are they adding to the music that's not in the original recording?

Edit: If you won't take my word for it, listen to Cajunner, he's on the money, I promise!! More volume is always perceived as sounding better even if it's from distortion (to an extent).


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## feeshta

Look, I know where you guys are coming from, but the bottom line is that a high quality "conventional" subwoofer just plain sounds more life-like than a Velodyne does with conventionally produced recordings. If the recordings were done differently, then the Velodyne would win, but they aren't, so the Velodyne just plain doesn't sound good. Everyone who listens to one knows that in their heart, but there are a certain % of the population who will convince themselves that the Velodyne sounds better because it has lower distortion. The original recordings were modified in a way that makes a conventional subwoofer, with it's inherent distortion, sound correct. That modification means that when you are listening to a Velodyne, you are actually listening to a distorted signal. The Velodyne reproduces it faithfully, but it's still a distorted signal, so it doesn't sound good. 

They are also just plain lacking in output by their design, 82-83 dB sensitively means they need roughly quadruple the power of an average Sub-woofer to reproduce the same SPLs and even then they do so without the same dynamics. A $2500 Velodyne 18 with 1000 watts couldn't even come close to my cousin's M&K with 200 watts and 2 12s, and the M&K blends remarkably well and is very musical. 

Bottom line is that until they release their own line of recordings, Velodyne is exclusively for techno-geeks who value numbers over the actual listening experience.


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## MarkZ

feeshta... you're talking about output (a complaint I've heard before) and distortion. How are you so certain that BOTH are at fault? Isn't it possible that you didn't like the velodyne because its output was bad? I'm also having a hard time believing that distortion is necessarily better. Especially when you consider that there are some modern designs from high output drivers where distortion is fairly low, and people don't seem to have the same complaints...


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## feeshta

MarkZ said:


> feeshta... you're talking about output (a complaint I've heard before) and distortion. How are you so certain that BOTH are at fault? Isn't it possible that you didn't like the velodyne because its output was bad? I'm also having a hard time believing that distortion is necessarily better. Especially when you consider that there are some modern designs from high output drivers where distortion is fairly low, and people don't seem to have the same complaints...


I'm so certain because I have talked to recording engineers, and they explained to me the process of mixing down the recording, and why it's done. The process is basically smoothing out the rough edges of the recording, because a subwoofer can't normally keep up with the dynamic response of the microphone that made the recording, due to the drastic difference in mass and energies involved. It would produce too much distortion with a conventional woofer, so they tone it down using various processors, scaling it back to the point where it sounds realistic. But with the Velodyne, this is just dynamics lost. 

There is nothing wrong with the Velodyne design. It's brilliant. It just doesn't work properly with most recordings. 

Maybe Velodyne should invent a dynamics restoration processor. Something that basically reverses the process and brings some of the dynamics back. Wouldn't be as good as the original recording, but might be better than normal Velodyne prozac.


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## MarkZ

feeshta said:


> I'm so certain because I have talked to recording engineers, and they explained to me the process of mixing down the recording, and why it's done. The process is basically smoothing out the rough edges of the recording, because a subwoofer can't normally keep up with the dynamic response of the microphone that made the recording, due to the drastic difference in mass and energies involved. It would produce too much distortion with a conventional woofer, so they tone it down using various processors, scaling it back to the point where it sounds realistic. But with the Velodyne, this is just dynamics lost.


Haha talk about a discussion coming full circle... Your description to me sounds like why recording engineers compress. :laugh:

But I don't think subwoofers themselves have a problem with dynamics, or that velodyne does appreciably better with dynamics. I think the explanation you got from those guys is addressing a different problem. You use compression even in live rigs too. It makes the music less dynamic, because there's such a thing as too dynamic of a sound.

The classic example of this is cymbal crashes. You use a compressor and an expander to reduce the dynamic range. If you don't do this, it sounds like ass.


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## feeshta

MarkZ said:


> Haha talk about a discussion coming full circle... Your description to me sounds like why recording engineers compress. :laugh:
> 
> But I don't think subwoofers themselves have a problem with dynamics, or that velodyne does appreciably better with dynamics. I think the explanation you got from those guys is addressing a different problem. You use compression even in live rigs too. It makes the music less dynamic, because there's such a thing as too dynamic of a sound.
> 
> The classic example of this is cymbal crashes. You use a compressor and an expander to reduce the dynamic range. If you don't do this, it sounds like ass.


As has been pointed out before, subwoofers in particular do have a problem with distortion, and distortion is perceived as volume by the human ear. The higher the dynamic headroom of the recording, the more trouble the subwoofer has reproducing it, and the more distortion. If you listen to an original master at high volume, it gets very ragged and boomy sounding in the bottom end. It just doesn't sound natural, so they tone it down to a point where the drivers can handle it. This is true throughout the frequency spectrum, but especially so in Subwoofers. The cymbal crash is just another illustration. They have to tone it down to a level where the drivers can accurately reproduce it. Nobody makes speakers in that frequency range that are digitally controlled like the velodynes though, at least not to my knowledge. 

While we are at it, we've already fleshed out the basics of a perfect audio world. Might as well finish up eh?

First you would record the live instrument at a very high sampling rate, in order to ensure than no nuance is lost. Then you would mix the recording so that it would sound proper on a sound system with a flat frequency response, and not compress it unless that was a musical taste choice of the artists. Then you would need speakers capable of delivering accuracy on the level the Velodyne offers with full range frequency response, and EQ to set the speaker system up for a flat frequency response. This would ensure reproducibility of the proper spectral balance, so that you get to hear the music as the artist intended. You would also need plenty of power of course, to ensure dynamics can be done justice. 

There, we just solved all the problems of the audio world. So, what next?


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## Hanatsu

What's up with these Velodyne subs? Are there seriously no other sub out there which can match it's non-linear distortion performance?

The enclosure itself will affect distortion profile too.


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## feeshta

Hanatsu said:


> What's up with these Velodyne subs? Are there seriously no other sub out there which can match it's non-linear distortion performance?
> 
> The enclosure itself will affect distortion profile too.


They are digitally controlled with a comparator or some other similar circuit. Basically it checks the cone's position thousands of times a second and corrects if needed to ensure that the actual output is as close to the input signal as possible. 

They patented it, so nobody else can use it.


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## RNBRAD

Now not all Velodynes are rated below 1/2% or whatever it is. I think the impact series is one of those higher distortion setups. Maybe why they call it impact?

Like you say, I think the Velo's with the Servo's are the cleanest subs in the world, if not close. So they are the best, or the bottom of the rung, however you want to look at it. It only gets better from there. Or again "worse" how you look at it.


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## MarkZ

feeshta said:


> As has been pointed out before, subwoofers in particular do have a problem with distortion, and distortion is perceived as volume by the human ear. The higher the dynamic headroom of the recording, the more trouble the subwoofer has reproducing it, and the more distortion. If you listen to an original master at high volume, it gets very ragged and boomy sounding in the bottom end. It just doesn't sound natural, so they tone it down to a point where the drivers can handle it. This is true throughout the frequency spectrum, but especially so in Subwoofers. The cymbal crash is just another illustration. They have to tone it down to a level where the drivers can accurately reproduce it. Nobody makes speakers in that frequency range that are digitally controlled like the velodynes though, at least not to my knowledge.


I don't think that's why they do it at all. Even at low volumes (_especially_ at low volumes), too dynamic sounds unnatural and sloppy.

Remember that wikipedia link I gave rnbrad last week for a completely different topic? Here's an excerpt. :laugh:



wikipedia said:


> Compression is often used in music production to make performances more consistent in dynamic range so that they "sit" in the mix of other instruments better and maintain consistent attention from the listener. Vocal performances in rock music or pop music are usually compressed in order to make them stand out from the surrounding instruments and to add to the clarity of the vocal performance.
> 
> Compression can also be used on instrument sounds to create effects not primarily focused on boosting loudness. For instance, drum and cymbal sounds tend to decay quickly, but a compressor can make the sound appear to have a more sustained tail. Guitar sounds are often compressed in order to obtain a fuller, more sustained sound.


The problem is that sometimes compression is abused. _Too much _compression can be a real problem. But music that's the victim of too much compression probably shouldn't be used as the standard to illustrate why velodyne subs fall short. I think so-called "well-recorded" material is the better metric here.

But, more importantly, the link between distortion and dynamics still isn't clear to me. Why would a low distortion sub like the velodynes do worse with compressed music than a higher distortion sub?


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## MarkZ

feeshta said:


> They are digitally controlled with a comparator or some other similar circuit. Basically it checks the cone's position thousands of times a second and corrects if needed to ensure that the actual output is as close to the input signal as possible.
> 
> They patented it, so nobody else can use it.


Some of you guys have a really weird understanding of how patents work.  Nobody else can use _their particular circuit_. That doesn't mean that nobody else can use cone positioning/feedback systems. There are a couple of other companies that make servo subwoofers.


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## feeshta

MarkZ said:


> Some of you guys have a really weird understanding of how patents work.  Nobody else can use _their particular circuit_. That doesn't mean that nobody else can use cone positioning/feedback systems. There are a couple of other companies that make servo subwoofers.


I've never seen another company advertising a servo system, but I don't follow home audio much these days. 

Either way, it doesn't change the fact that that style of sub sounds neutered and unnatural.


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## MarkZ

"fact"...


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## thehatedguy

Velodynes are nice, I had a pair of the 10s.

However back in the early 90s their claim of the lowest distortion subs for the car was valid. 20 years later...I doubt it. And if not, I doubt you could hear the differences in distortion between those and a good modern sub...especially in the subbass.

One of my Velodynes rotted and wasn't able to be serviced, but I did get the servos and have the controller board. Have thought about retro fitting them to a modern sub, but don't know how well the controller would do with a modern sub and it's HIGH (compared to 1992) excursion. Then there is the output limiting that I don't know if I would really like.


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## ChrisB

feeshta said:


> I've never seen another company advertising a servo system, but I don't follow home audio much these days.


Never heard of these guys before: Servo subwoofers •Rythmik Audio Direct Servo subwoofers

I wanted to get a couple, but my wife won't let me put them in the living room. Well, I could, but she wouldn't be happy, which in turn would mean that I wouldn't be happy. 

As a result, I may be going with plan B... IB subwoofers in the attic.


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## STROKD

lmmfao.:laugh4: amps dont change sound... hahahahahahaha


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## Golden Ears

Depending on your speaker's resolution and how reactive a load your speakers present, amps can Audi ly make a difference or not.


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## MarkZ

Why are we starting the thread from the beginning?


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## RNBRAD

I guess the question was never answered. Was there one? :laugh: I have learned some things from this thread and others is the higher end of the "high-end" amps like Brax, Sinfoni, McIntosh, even Halcro, people almost always say they sound "under powered" or "lack meat" or "compressed". This is very common among these brands I've noticed. I've never heard this among any other brands as a whole like these 4. They are probably the most sonically transparent and accurate amplifiers the car audio world (home for Halcro) has ever known. But yet time after time people will say the same things. Has SQ changed? Perception sure has because an amplifier that "adds nothing" better than everyone else is deemed "flat", "underpowered", "compressed". I don't get it?  People are hearing something. I think it's probably the clipping signature of cheaper amplifiers that people have grown accustom to and now prefer and like that added colour. I guess it would be interesting to compare those signatures among different amps. Tubes have the most sonically sought out clipping signature. Company's trying to mimic this? improve upon it? add their own flavor of it? Can you make an amplifier too sonically transparant? Maybe those clean amps need to add an electronic algorythm of DSP to mimic the sound of a clipping tube or something. :laugh:


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## soundhertz

That is why I drive a 5 series BMW. Quiet. I can hear the incredible detail of my Pioneer ODR system at 70 mph. Trust me on that.


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## RNBRAD

Well I was talking about high end SQ amps specifically. Sure driver technology has changed power compression, so the more efficient the speaker design the louder and better SQ it may have perceptually. But if drivers today don't experience power compression like drivers of yesteryear, would that then mean that any amplifier is more capable of reaching its limits with speakers manufactured today?


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## feeshta

soundhertz said:


> That is why I drive a 5 series BMW. Quiet. I can hear the incredible detail of my Pioneer ODR system at 70 mph. Trust me on that.


My 540i is driving me nuts right now with a droning sound coming from the rear. I think it's the snow tires I have on it for the winter wearing improperly, but in any case it's maddening.


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## Golden Ears

feeshta said:


> My 540i is driving me nuts right now with a droning sound coming from the rear. I think it's the snow tires I have on it for the winter wearing improperly, but in any case it's maddening.


Fix this with this simple EQ tip:

1. Get a copy of Pink Floyd's Dark Side of the Moon. Mobile Fidelity's Master recording is better as it was recorded at a lower levela nd lower noise floor. Put this in your Head unit and put it on at a level that is audible but not loud....about 45-50db max.

2. Carefully while going 70mph. Start track 1. Put on single repeat. Ideally the first 20 seconds if your head unit allows looping.

3. Within 5 seconds..AND Quickly while staring straight ahead - Have your avatar put her globes over your ears and you will hear blissful silence- the road noise will vanish completely- (NOW only the heart beat from Dark side of the Moon will remain) she will have to be behind your seat to drive and still see anything.

You will no longer hear the annoying roar of your winter tires. Problem solved. Play this song continuously in your car, you will never tire of it. 

If you can not get this to work for you, let me drive your car and use her to get it just right...likely there are a lot of DIYMA enthusiasts in Baltimore that can help, but failing that I can make sure it will work, nearly 95% of California women even get surgically altered after 30 to help with this acoustic problem, which makes them more audiophile friendly than Baltimore women. 

California is car crazy.


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## feeshta

Golden Ears said:


> Fix this with this simple EQ tip:
> 
> 1. Get a copy of Pink Floyd's Dark Side of the Moon. Mobile Fidelity's Master recording is better as it was recorded at a lower levela nd lower noise floor. Put this in your Head unit and put it on at a level that is audible but not loud....about 45-50db max.
> 
> 2. Carefully while going 70mph. Start track 1. Put on single repeat. Ideally the first 20 seconds if your head unit allows looping.
> 
> 3. Within 5 seconds..AND Quickly while staring straight ahead - Have your avatar put her globes over your ears and you will hear blissful silence- the road noise will vanish completely- (NOW only the heart beat from Dark side of the Moon will remain) she will have to be behind your seat to drive and still see anything.
> 
> You will no longer hear the annoying roar of your winter tires. Problem solved. Play this song continuously in your car, you will never tire of it.
> 
> If you can not get this to work for you, let me drive your car and use her to get it just right...likely there are a lot of DIYMA enthusiasts in Baltimore that can help, but failing that I can make sure it will work, nearly 95% of California women even get surgically altered after 30 to help with this acoustic problem, which makes them more audiophile friendly than Baltimore women.
> 
> California is car crazy.


She says she hates Pink Floyd, so unfortunately we will have to try another method. :laugh: 

She is car crazy though. We actually met online on a car message board and she used to be really into drag racing her car. She also did not require surgical enhancement for optimal performance in your solution.  

Unfortunately her taste in music and mine don't mesh up too well. She's Russian, and likes their pop type stuff. Not my cup of tea. I'm more happy with some Tool or Silversun pickups or something, which she can't stand. The car is my haven for listening to what I choose.


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