# Do all competently designed and level matched amps/head units sound the same?



## Niebur3 (Jul 11, 2008)

I am conducting a simple poll to see what the opinions are form the DIY community regarding the sonic differences (if any) between head units and amplifiers. This is simply what you believe.

Please keep it to only a poll so this thread does not deteriorate and get shut down (i.e, vote, but keep your comments to yourself). This is a real hot spot that has very strong supporters on both sides. 

****This poll is NOT intended to prove anything as perception can be vastly wrong, and just because one side will win this poll does NOT mean their perception is fact or accurate.****

*****If you vote yes, also vote if you think it matters at 80 mph - This poll allows you to select more than 1 answer*****


----------



## Niebur3 (Jul 11, 2008)

Thanks for those who chose to move this to the "no question is dumb forum", since this is an opinion poll. It won't stop the results and I am sure many regard it as a dumb question on both sides of the topic. Thanks to all that have voted!


----------



## 89grand (Nov 23, 2006)

I say yes, with "competently designed" being the key word here, because if a headunit/amp is competently designed, it should be low noise with a completely flat frequency response.


----------



## Niebur3 (Jul 11, 2008)

89grand said:


> I say yes, with "competently designed" being the key word here, because if a headunit/amp is competently designed, it should be low noise with a completely flat frequency response.


Thanks


----------



## lycan (Dec 20, 2009)

no offense intended, but the poll is silly. The correct answer is _not_ dependent on ... in fact, only loosely correlated with ... a majority opinion on an audio message board.

The only _real_ question of interest is : do we have a comprehensive set of specifications that completely describe & determine "the sound" of purely electronic devices (lets not include loudspeakers, for now)? All data ... all scientific investigation, all theory, and all tests ... leads to an affirmative answer.

If two pieces of audio electronics have the same gain, power, frequency response, noise & distortion ... then what is the parameter by which they CAN sound different?

What is it?

The type of solder used? If it doesn't impact gain, power, frequency response, noise or distortion ... then it is irrelevant.

The type of capacitors used? If it doesn't impact gain, power, frequency response, noise & distortion ... then it is irrelevant.

The type of wire used? If it doesn't impact gain, power, frequency response, noise & distortion ... then it is irrelevant.

By the way ... nobody in their right mind says that all amps sound the same. I can pull two amps off the same production line, and set their gain controls different by 0.25dB. They WILL sound different. However, the REASON they sound different is because that gain knob happens to impact one of these : gain, power, frequency response, noise or distortion.

Conversely, there's always someone who says : "I swapped amps, and i KNOW they sounded different !!!!"

That's a meaningless statement. What WOULD be a meaningful statement is : "I swapped amps, and i carefully measured gain, power, frequency response noise & distortion to make sure these classic parameters were the same. Then, in a controlled listening test where the name brands were hidden, a statistically significant difference was identified. And because i carefully eliminated the classic variables of gain, power, frequency response, noise & distortion, i have come to the conclusion that the difference could NOT be attributed to any of these classic variables".

Of course, that statement has never been offered in the history of the world.

So the question always remains : How do you know whether or not the difference you heard can be attributed to : gain, power, frequency response, noise or distortion?

How could anyone possibly answer this question? Do we have no choice but to wander aimlessly in the dark ... no choice but to rely on guru opinions and internet polls? Is there no logical process to determine if differences can be attributed to gain, power, frequency response, noise & distortion? What's the process to determine if these specs are indeed comprehensive?


----------



## Oliver (Jun 25, 2007)

*I've seen no sign of competency here.*


----------



## audiogodz1 (Jan 5, 2010)

Baba Booey Zed Audio Baba Booey Zed Audio Baba Booey


----------



## MarkZ (Dec 5, 2005)

I don't understand the purpose of this poll. All these subjects have been discussed dozens, maybe even hundreds, of times in this forum.


----------



## Niebur3 (Jul 11, 2008)

MarkZ said:


> I don't understand the purpose of this poll. All these subjects have been discussed dozens, maybe even hundreds, of times in this forum.


Yes this has been discussed, I was looking to see how many actually think one way or the other. It is a little hard to read through endless threads to determine that. Discussed is a nice word to describe it by the way .


----------



## DS-21 (Apr 16, 2005)

lycan said:


> no offense intended, but the poll is silly. The correct answer is _not_ dependent on ... in fact, only loosely correlated with ... a majority opinion on an audio message board.


Damn. I hit reply expressly to say just that. Well, I wanted to put it more coarsely: reality doesn't give a damn what a poll says. The earth doesn't magically become a cube, or President Obama a Muslim, just because people are stupid enough to answer that way in a poll.

(And yes, at this juncture in the polling at least there are at least 17 people in active denial of reality. They probably just got back from Glenn Beck's klansman gathering in Washington.)

But at least there's one point on which at least the way we would phrase the issue, if not our actual position, seems to differ a smidgen.



lycan said:


> The only _real_ question of interest is : do we have a comprehensive set of specifications that completely describe & determine "the sound" of purely electronic devices (lets not include loudspeakers, for now)? All data ... all scientific investigation, all theory, and all tests ... leads to an affirmative answer.


I would phrase the only real question as being: in competently designed, nonbroken equipment properly specified for a reasonable application, has anyone ever heard a difference between devices under test? The answer, in case it wasn't obvious, is _once:_ a nonbroken and competently designed CD player with 14-bit resolution (I believe the first model of CD player sold for home use) sounded different from a nonbroken and competently designed CD player with 16-bit resolution (a generation or two more advanced, but we're still talking early 1980s here).

If it's not audible, it's just not worth discussing if one's goal is reproducing music. 

That's of course not to say that there are any number of subjective (looks, brand loyalty/snobbery, color, perceived quality, perceived value, etc.) or objective (I/O layout, projected resale value, features, price, form factor, etc.) properties that can distinguish one digital source/amp/wire from another. But non of those properties have anything to do with the "sound" of the box or wire in question.


----------



## Niebur3 (Jul 11, 2008)

DS-21 said:


> Damn. I hit reply expressly to say just that. Well, I wanted to put it more coarsely: reality doesn't give a damn what a poll says. The earth doesn't magically become a cube, or President Obama a Muslim, just because people are stupid enough to answer that way in a poll.


Wow, to get a law degree, I thought you had to learn how to actually read? I guess not . It does explain a lot though!



Niebur3 said:


> ****This poll is NOT intended to prove anything as perception can be vastly wrong, and just because one side will win this poll does NOT mean their perception is fact or accurate.****


----------



## DS-21 (Apr 16, 2005)

Actually, one thing one learns when one goes to a real school is how to read between the lines. Obviously, you were trolling for support for some of your more idiotic premises. Any reasonable person could see that.


----------



## SoundChaser (Apr 3, 2009)

lycan said:


> no offense intended, but the poll is silly. The correct answer is _not_ dependent on ... in fact, only loosely correlated with ... a majority opinion on an audio message board.
> 
> The only _real_ question of interest is : do we have a comprehensive set of specifications that completely describe & determine "the sound" of purely electronic devices (lets not include loudspeakers, for now)? All data ... all scientific investigation, all theory, and all tests ... leads to an affirmative answer.
> 
> ...



So will I be wasting my time trying new op amps?

I was planning on trying these:

Digi-Key - LME49720NA-ND (Manufacturer - LME49720NA/NOPB)


----------



## lycan (Dec 20, 2009)

SoundChaser said:


> So will I be wasting my time trying new op amps?
> 
> I was planning on trying these:
> 
> Digi-Key - LME49720NA-ND (Manufacturer - LME49720NA/NOPB)


Which parameter do you hope to improve :

power, gain, frequency response, noise or distortion?

Which of these is currently unsatisfactory, in your amp (or other gadget)?

It's VERY instructive to understand that ALL of these parameters are QUANTIFIABLE. You need not spend your money because some internet guru described how much more "air" or "speed" or "lush-osity" you'll get with new opamps.


----------



## Oliver (Jun 25, 2007)

Different* "air"* can be had in the mountains [ thinner if U will ] for *"speed" *going down a mountain is exciting and *"lush-osity"* is what you'll be hoping you land in if you drive off the side of a mountain.


----------



## Niebur3 (Jul 11, 2008)

DS-21 said:


> Actually, one thing one learns when one goes to a real school is how to read between the lines. Obviously, you were trolling for support for some of your more idiotic premises. Any reasonable person could see that.


Remember, when you assume you make an ass of yourself . You seem to be an expert at that!


----------



## MarkZ (Dec 5, 2005)

I'm intrigued by the fact that when lycan says something, nobody gives him ****, but when DS-21 says the _same exact thing_ people jump up his ass.


----------



## lycan (Dec 20, 2009)

MarkZ said:


> I'm intrigued by the fact that when lycan says something, nobody gives him ****, but when DS-21 says the _same exact thing_ people jump up his ass.


probly cuz lycan didn't mention President Beck


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> Which parameter do you hope to improve :
> 
> power, gain, frequency response, noise or distortion?
> 
> ...


I understand what you are saying, but how without having extremely expensive test equipment are we able to know the "power, gain, frequency response, noise, or distortion" of the amplifier/headunit we intend to buy? There does not seem to be a standard that everyone actually uses to test amplifiers/headunits. You see all the time where the published specs vary in some way or another from the specs on the "birth certificate" included with the amplifier. Even taking that out of the mix, manufacturers seem to test under various conditions (hot vs cold), many to the amps advantage to make the specs look as good as possible. Do different caps, resistors, etc., perform differently when hot/cold vs others...and can this effect the sound quality? What about a cheap internal part being substituted that has a larger variance for change/failure? How many of us actually measure the amps/headunits we buy to compare against the published specs....how do we know it performs like it says it should? 

With that said, the word "competently designed" seems to get thrown around all the time without a definition attached. How do I (an average consumer) know which products are competently designed before I purchase? Do a trust a "brand name" company? I mean, its not like they never make mistakes, develop new ways to build (i.e. class D, etc.), try to cut costs or anything like that. 

It is hard more me to read that people are not able to hear a 1 dB variance, but on the other be told that I am required to level match to better than a .25 dB difference and that is the reason there may be an audible difference between 2 amp or headunits.


----------



## Niebur3 (Jul 11, 2008)

MarkZ said:


> I'm intrigued by the fact that when lycan says something, nobody gives him ****, but when DS-21 says the _same exact thing_ people jump up his ass.


Lycan does it without being an ass and insulting people....that is the difference!


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> I understand what you are saying, but how without having extremely expensive test equipment are we able to know the "power, gain, frequency response, noise, or distortion" of the amplifier/headunit we intend to buy? There does not seem to be a standard that everyone actually uses to test amplifiers/headunits. You see all the time where the published specs vary in some way or another from the specs on the "birth certificate" included with the amplifier. Even taking that out of the mix, manufacturers seem to test under various conditions (hot vs cold), many to the amps advantage to make the specs look as good as possible. Do different caps, resistors, etc., perform differently when hot/cold vs others...and can this effect the sound quality? What about a cheap internal part being substituted that has a larger variance for change/failure? How many of us actually measure the amps/headunits we buy to compare against the published specs....how do we know it performs like it says it should?
> 
> With that said, the word "competently designed" seems to get thrown around all the time without a definition attached. How do I (an average consumer) know which products are competently designed before I purchase? Do a trust a "brand name" company? I mean, its not like they never make mistakes, develop new ways to build (i.e. class D, etc.), try to cut costs or anything like that.
> 
> It is hard more me to read that people are not able to hear a 1 dB variance, but on the other be told that I am required to level match to better than a .25 dB difference and that is the reason there may be an audible difference between 2 amp or headunits.


fair questions.

You can : 

1. Trust the manufacturer specs ... based on brand name, longevity, or reputation.
2. Trust the manufacturer specs because they are subject to "regulation" by an industry association.
3. Trust manufacturer specs, only after they are subject to (verified by) independent third-party measurements.
4. Measure yourself ... some might not be as hard as you think!


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> I understand what you are saying, but how without having extremely expensive test equipment are we able to know the "power, gain, frequency response, noise, or distortion" of the amplifier/headunit we intend to buy? There does not seem to be a standard that everyone actually uses to test amplifiers/headunits. You see all the time where the published specs vary in some way or another from the specs on the "birth certificate" included with the amplifier. Even taking that out of the mix, manufacturers seem to test under various conditions (hot vs cold), many to the amps advantage to make the specs look as good as possible. Do different caps, resistors, etc., perform differently when hot/cold vs others...and can this effect the sound quality? What about a cheap internal part being substituted that has a larger variance for change/failure? How many of us actually measure the amps/headunits we buy to compare against the published specs....how do we know it performs like it says it should?
> 
> With that said, the word "competently designed" seems to get thrown around all the time without a definition attached. How do I (an average consumer) know which products are competently designed before I purchase? Do a trust a "brand name" company? I mean, its not like they never make mistakes, develop new ways to build (i.e. class D, etc.), try to cut costs or anything like that.
> 
> It is hard more me to read that people are not able to hear a 1 dB variance, but on the other be told that I am required to level match to better than a .25 dB difference and that is the reason there may be an audible difference between 2 amp or headunits.


You should be able to put together an adequate measurement rig for well under $100, not including software licenses (which some may or may not consider an expense ). Harmonic distortion adds a slight layer of difficulty, but that's why a lot of people just group THD+N (which really means ... "all the crap that ain't signal").


----------



## lycan (Dec 20, 2009)

Think of the small set of meaningful measurements & specs as the "******** filter" that prevents you from spending needlessly. All comments, opinions, rumors, biases and prejudices about electronic audio equipment ENTER the "bs filter", and what comes OUT are the only things that sonically matter


----------



## SoundChaser (Apr 3, 2009)

lycan said:


> Which parameter do you hope to improve :
> 
> power, gain, frequency response, noise or distortion?
> 
> ...


I guess the engineers involved in designing and testing would be biased towards their own product.

National opamp inflation - diyAudio

Ah well, it’s a fairly inexpensive experiment. If the sound improvement is only in my mind, I’ll take it. Life’s a placebo.


----------



## lycan (Dec 20, 2009)

SoundChaser said:


> I guess the engineers involved in designing and testing would be biased towards their own product.
> 
> National opamp inflation - diyAudio
> 
> Ah well, it’s a fairly inexpensive experiment. If the sound improvement is only in my mind, I’ll take it. Life’s a placebo.


ur _really_ not askn me to read 29 pages (and counting) on diyaudio about opamps, are ya?  :surprised: 

fort what it's worth ... and this lil tidbit should be worth exactly nothing, in this context ... i've designed, tested and put-into-production _dozens_ of audio opamps. None of them "stand alone" products, but rather as part of signal processing chains in audio ADCs, DACs, etc. duzn't mean nuthn ...

Bottom line is invariant : As it passes through the opamp, the audio signal is _electrical_ in nature (rather than mechanical, or acoustical). It would follow, then, that the specs that matter are _electrical_ ones  Things like noise, slew rate, stability, load driving ability, PSRR, etc. It's all quantifiable ... and if it doesn't improve measurements (you know the ones) of the end-product, then it won't improve the "sound"


----------



## Niebur3 (Jul 11, 2008)

MarkZ said:


> You should be able to put together an adequate measurement rig for well under $100, not including software licenses (which some may or may not consider an expense ). Harmonic distortion adds a slight layer of difficulty, but that's why a lot of people just group THD+N (which really means ... "all the crap that ain't signal").





lycan said:


> Think of the small set of meaningful measurements & specs as the "******** filter" that prevents you from spending needlessly. All comments, opinions, rumors, biases and prejudices about electronic audio equipment ENTER the "bs filter", and what comes OUT are the only things that sonically matter


So that covers the specs...what about the:

With that said, the word "competently designed" seems to get thrown around all the time without a definition attached. How do I (an average consumer) know which products are competently designed before I purchase? Do a trust a "brand name" company? I mean, its not like they never make mistakes, develop new ways to build (i.e. class D, etc.), try to cut costs or anything like that.


----------



## DS-21 (Apr 16, 2005)

The universe of incompetently designed digital sources and amplifiers is extremely small, from my experience. In fact, I'm going to do a level-matched single-blind test between an expensive amp from a brand I'd never consider buying (Arc KS125.4 Mini) and my old Rockford_ Fosgate_ Power 300 MOSFET. Yes, the test is being run on mains, rather than subwoofers! (I'm not stupid.) His car, his speakers, his music. 

What am I getting in return? A check for Pakistani flood relief work for $200, and the expensive amp. If the coin comes up heads 10x in a row, then I lose the Power 300 and give $2000 to flood relief. (Admittedly, that means I'd only lose the amp, because the contribution is just a small part of a larger one I've already committed to give.)


But to answer your question, I think, here's a reasonable set of rules of thumb:

If it's from a reasonably well-known maker with a reputation for honesty, trust unless you have a specific reason not to. (For instance, there have been claims that some Clarion HU's and older Alpine PDX amps have self-noise. I take no position on the truth of those claims, because I've not used either one. But they're out there, and claims of noise are reasonable, so I would not buy such a thing blind.)

If there are reviews of other pieces of kit from that maker and they generally test well enough and true-to-spec, trust a little more.

If it's on the extreme low end or the high end of the market, verify rather than trust.

If the marketer spews technobabble that looks like it's designed to be flypaper for audiophools, and it's on the expensive side, don't trust and it's probably not worth your time to verify.

If the marketer spews technobabble about mods to a different _brand_ of parts inside, assume that they're clueless idiots, hacks, and con-men.

If you hear someone talking about a commodity part (from a sonic perspective) "sounding better," assume they are either scammers OR the piece of kit in question is incompetently designed OR the piece of kit in question is designed with something other than fidelity to the input signal.


----------



## Niebur3 (Jul 11, 2008)

DS-21 said:


> The universe of incompetently designed digital sources and amplifiers is extremely small, from my experience. In fact, I'm going to do a level-matched single-blind test between an expensive amp from a brand I'd never consider buying (Arc KS125.4 Mini) and my old Rockford_ Fosgate_ Power 300 MOSFET. Yes, the test is being run on mains, rather than subwoofers! (I'm not stupid.) His car, his speakers, his music.
> 
> What am I getting in return? A check for Pakistani flood relief work for $200, and the expensive amp. If the coin comes up heads 10x in a row, then I lose the Power 300 and give $2000 to flood relief. (Admittedly, that means I'd only lose the amp, because the contribution is just a small part of a larger one I've already committed to give.)


Are you able to divulge who is doing the test against you? I would be more interested if the test involved a Class D full range (HD 600/4) against a Arc SE edition or something along those lines. Also, I would never agree to 10x in a row, 8-9/10 still proves an audible difference and prevents against luck IMO. Is there going to be a break in time or is it left, right, left right, picking which is which?


----------



## SoundChaser (Apr 3, 2009)

lycan said:


> ur _really_ not askn me to read 29 pages (and counting) on diyaudio about opamps, are ya?  :surprised:
> 
> fort what it's worth ... and this lil tidbit should be worth exactly nothing, in this context ... i've designed, tested and put-into-production _dozens_ of audio opamps. None of them "stand alone" products, but rather as part of signal processing chains in audio ADCs, DACs, etc. duzn't mean nuthn ...
> 
> Bottom line is invariant : As it passes through the opamp, the audio signal is _electrical_ in nature (rather than mechanical, or acoustical). It would follow, then, that the specs that matter are _electrical_ ones  Things like noise, slew rate, stability, load driving ability, PSRR, etc. It's all quantifiable ... and if it doesn't improve measurements (you know the ones) of the end-product, then it won't improve the "sound"



Yea, I was expecting you to read it all. Then type out a report so I can read it by the time I got home from work and finished dinner.

Seriously though, you’re going to ruin my placebo. But then again, I stare at goats.:laugh: Just saw the movie yesterday. Kinda strange….

Sometimes what works on paper doesn’t work in real life. And visa-versa.


----------



## MarkZ (Dec 5, 2005)

SoundChaser said:


> Sometimes what works on paper doesn’t work in real life. And visa-versa.


Only if you don't understand the system. Then, you identify what part you missed and add it to the paper. 

Basic things, like dimension reduction of simple analog signals, is well-known and has been for a very very long time. We're not talking about landing a spacecraft on a different planet and the millions of variables it encompasses.

It's also important to point out that the things lycan is talking about are NOT the outcome of scientific investigation, nor is it engineering per se. It's mathematics, which is ultimately derived from logic. Reducing a signal (electrical or otherwise) into its component parts is not the outcome of scientific inquiry or discoveries. It's merely the application of mathematical (ie. logical) transforms applied to a measurable quantity.

So, when someone says, "we can represent this signal by X, Y, and Z", this doesn't come from experimentation. It's indisputable fact.


----------



## 60ndown (Feb 8, 2007)

lycan said:


> fair questions.
> 
> You can :
> 
> ...


id say you can also

5, trust your own ears if you have spent some time with a product that sounds like any of the above.


----------



## 60ndown (Feb 8, 2007)

MarkZ said:


> Reducing a signal (electrical or otherwise) into its component parts is not the outcome of scientific inquiry or discoveries. It's merely the application of mathematical (ie. logical) transforms applied to a measurable quantity.


or,

all good amps sound the same.


----------



## DS-21 (Apr 16, 2005)

Niebur3 said:


> Are you able to divulge who is doing the test against you?


Don't know if the person is on this forum (or any other). 



Niebur3 said:


> I would be more interested if the test involved a Class D full range (HD 600/4) against a Arc SE edition or something along those lines.


Why? If the person had a bigger Ubuy amp, or something "high end" such as a McIntosh or old Adcom 4702, that would've been the amp. 



Niebur3 said:


> Also, I would never agree to 10x in a row, 8-9/10 still proves an audible difference and prevents against luck IMO.


Do the math and tell me what's statistically significant positive for 10 reps. Regardless, when someone says, "every time, it's night and day better" another would be a fool to not get that down.



Niebur3 said:


> Is there going to be a break in time or is it left, right, left right, picking which is which?


Break in time? What the **** does that even mean?

What's going to happen is I'm going to bring a book and switch amps whenever asked for a sighted listening. When the guy thinks he has a handle on the "differences" between them, he goes blind. I hook up one amp, then the other, in a random order. I tell him which is which. Then I hook up one of the amps again, and tell him which it is. Then I hook up one of the two amps, and ask him if it's the same amp or if it's the other one. 

Hopefully, I'll get my amp and flood victims will get their money in under 5-6 hours...


----------



## lycan (Dec 20, 2009)

60ndown said:


> id say you can also
> 
> 5, trust your own ears if you have spent some time with a product that sounds like any of the above.


... notoriously untrustworthy, easily fooled, unreliable and _extraordinarily_ influenced by extraneous variables in the context of scientific testing  That's why human ears are not routinely used in the design and testing of audio electronics.

Certainly, ears are the "final audience" ... but almost _never_ relied upon for the purposes of design, evaluation & production test.

If a certain piece of audio electronics meets a well-established set of design parameters, developed over decades of rigorous scientific investigation, then we _know_ how it will sound. That foundation of science allows us to design & test all manner of audio electronic devices without relying on a pair of "golden ears" or self-proclaimed "gurus" during design, simulation, evaluation & production test. 

And, perhaps most importantly, it allows an educated consumer to _compare_ and _evaluate_ competitive products without worrying : how we can perform a proper double-blind listening test, what if i have a headache on the scheduled listening day, what source material should i pick to expose possible design flaws, etc etc etc

The sonic performance itself is ART, but the channel through which we listen to it is SCIENCE  Never confuse the Mona Lisa with the glass in front of her.


----------



## TREETOP (Feb 11, 2009)

lycan said:


> ... notoriously untrustworthy, easily fooled, unreliable and _extraordinarily_ influenced by extraneous variables in the context of scientific testing  That's why human ears are not routinely used in the design and testing of audio electronics...


Then why would it matter if two amps sound the same anyway, since our ears can't be trusted to hear the same thing twice?


----------



## rexroadj (Oct 31, 2008)

MarkZ said:


> Only if you don't understand the system. Then, you identify what part you missed and add it to the paper.
> 
> Basic things, like dimension reduction of simple analog signals, is well-known and has been for a very very long time. We're not talking about landing a spacecraft on a different planet and the millions of variables it encompasses.
> 
> ...


Not that this a discussion I want any part of, but.... This is one of the best descriptions of this I have heard on here (obviously I have not read them all so please, anyone else do not take offense) 
Well said!


----------



## Niebur3 (Jul 11, 2008)

Originally Posted by MarkZ 
Only if you don't understand the system. Then, you identify what part you missed and add it to the paper. 

Basic things, like dimension reduction of simple analog signals, is well-known and has been for a very very long time. We're not talking about landing a spacecraft on a different planet and the millions of variables it encompasses.

It's also important to point out that the things lycan is talking about are NOT the outcome of scientific investigation, nor is it engineering per se. It's mathematics, which is ultimately derived from logic. Reducing a signal (electrical or otherwise) into its component parts is not the outcome of scientific inquiry or discoveries. It's merely the application of mathematical (ie. logical) transforms applied to a measurable quantity.



rexroadj said:


> Not that this a discussion I want any part of, but.... This is one of the best descriptions of this I have heard on here (obviously I have not read them all so please, anyone else do not take offense)
> Well said!


I will start off by saying I am a math/logic guy myself. With that said, lets assume (something I hate to do) a manufacturer does the "math" and come up with a "perfect" design for an amp, again, its not rocket science. Math says value A x B = C. My point is we the make all the parts that go into the amps (human element involved). We then allow a certain amount of variance within the parts made. There are parts at the high side of what is tolerated, on the low side of what is tolerated, and outside what is tolerated. More expensive parts are said to have a lower variance/failure rate (don't know if this is true or not). 

What happens when a .02 part is chosen over a .10 part which causes a much higher variance initially or under the stress of actually driving the speakers? Would you not have a competently designed amp, which in a perfect world would sound the same as any other amp, sound different because of the variance of the parts used? Again, I don't know and I am asking....maybe the variance is not enough to be audible in the final output or the manufacturers account for that variance in the initial design somehow?


----------



## 60ndown (Feb 8, 2007)

lycan said:


> ... *human ears are* notoriously untrustworthy, easily fooled, unreliable and _extraordinarily_ influenced by extraneous variables in the context of scientific testing


so it would be more fair to use a microphone and a laptop to judge car audio 
competitons instead of people?


----------



## 60ndown (Feb 8, 2007)

TREETOP said:


> Then why would it matter if two amps sound the same anyway, since our ears can't be trusted to hear the same thing twice?


exaccharry. buy a nice clean quality amp and call it good, no need to $$spend$$ the last 98%


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> Originally Posted by MarkZ
> Only if you don't understand the system. Then, you identify what part you missed and add it to the paper.
> 
> Basic things, like dimension reduction of simple analog signals, is well-known and has been for a very very long time. We're not talking about landing a spacecraft on a different planet and the millions of variables it encompasses.
> ...


Variance is fully accounted for in any good circuit design, so that impact to key parameters over bandwidth of interest is nill.

Example : AC coupling capacitors.

Nominal value will result in high-pass, nominal 3dB freq at 4.0 Hz. If the cap value is 20% too low, that high-pass 3dB freq will "move" up to 5.0 Hz. Impact at 20 Hz : inconsequential.

Example : Gain-setting resistor ratio.

Nominal value results in a voltage gain of 20.0 for the amplifier. If the resistor ratio is in error by 1%, the gain changes to 20.2. Impact : gain knob compensates.


----------



## lycan (Dec 20, 2009)

60ndown said:


> so it would be more fair to use a microphone and a laptop to judge car audio
> competitons instead of people?


i've restricted my comments to audio electronics, and specifically *not* included loudspeakers.

NOT because loudspeakers are somehow mysteriously "beyond the realm" of science, but because they add a few dimensions that significantly complicate the analysis.

HOWEVER ... any good loudspeaker/crossover designer WILL rely heavily on measurements --in the room of interest-- whenever possible.


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> I will start off by saying I am a math/logic guy myself. With that said, lets assume (something I hate to do) a manufacturer does the "math" and come up with a "perfect" design for an amp, again, its not rocket science. Math says value A x B = C. My point is we the make all the parts that go into the amps (human element involved). We then allow a certain amount of variance within the parts made. There are parts at the high side of what is tolerated, on the low side of what is tolerated, and outside what is tolerated. More expensive parts are said to have a lower variance/failure rate (don't know if this is true or not).
> 
> What happens when a .02 part is chosen over a .10 part which causes a much higher variance initially or under the stress of actually driving the speakers? Would you not have a competently designed amp, which in a perfect world would sound the same as any other amp, sound different because of the variance of the parts used? Again, I don't know and I am asking....maybe the variance is not enough to be audible in the final output or the manufacturers account for that variance in the initial design somehow?


To be clear, I wasn't referring to amplifier design. I was addressing people's skepticism that we can represent a signal in its entirety in terms of other more convenient descriptions (eg. freq resp, distortion, noise, ...).

As for your question... yes, variance sometimes has an impact. In other cases, variance has no impact whatsoever. It all depends on the part's location and function in the circuit. Most component values are arbitrarily chosen -- you have an acceptable range to accomplish its task, not an ideal single value. Usually a good rule of thumb is that good designs make component tolerances less important.


----------



## lycan (Dec 20, 2009)

cajunner said:


> I disagree with Mark Z, lycan, and DS-21 on the specifics of intelligibility.
> 
> There is the simple, dumbed down version we're treated to here, and then there is the realm of time-based improvement.
> 
> Is it possible that as a filtering device, the human hearing mechanism is simply too crude, too diverse and too subjective as a measurement device, such that the five distinctly measurable criteria lycan uses to divide fact from fiction, are only the five most important parameters, ones that can be measured by media that "moves faster" in correlation?


no, it's not possible.

What you're missing is that the devices under discussion are _electrical_. Their outputs are _electrical signals_. And electrical theory is very well established, and _very comprehensive_.

There's only a handful of parameters that can describe an electrical signal. These parameters have equivalent descriptions in the time domain, and frequency domain. There's simply no other "secret domain" that human hearing knows about *wink wink* but that somehow escapes the scrutiny of well-established electrical theory and analysis.

If the voltages presented to two loudspeakers are identical, according to all electrical measurement and theory, there's simply no way for the loudspeakers to sound "different" because of some mysterious, magical realm that only human hearing is privy to.


> I'm not disagreeing with the principle of this supposition, because I am pretty sure Richard Clark did his turn on the catwalk without tripping, but more a consternation of reciprocal ideas gone awry, as I truly wish to remove the scientist from his lab.
> 
> Let's suppose that it were possible to create an amp identical to another, except for the ability to create power over time, something like "Dynamic Power on Demand" or non-negative feedback designs that let hysteresis or back emf commingle the signal, would these then fall under "noise, distortion, gain, freq response, etc."?
> 
> ...


A laboratory IS the "real world" ... the only difference being that it's a world where variables are controlled, so that cause & effect can be determined.

Richard Clark's test can't be beaten, because it simply demonstrates the principles we're discussing. If two amplifiers deliver the same ELECTRICAL signal to a loudspeaker, there's simply NO WAY they can "sound" different. What constitutes "the same" as far as electrical signals are concerned? It's simple : gain, power, frequency response, noise & distortion. There's no other "hidden realm" outside the scope of Fourier Analysis, Parseval's Theorem, etc. that *only* human hearing "knows about" 

Is there another domain for describing electrical signals ... other than the time domain & frequency domain?

*Voodoo priests and audiophiles don't understand this point : if the electrical signals presented to a loudspeaker are the same, then the speaker has no choice but to respond the same ... and human hearing is not uniquely "clued-into" some magical realm where this simple, logical conclusion is somehow false.*

Want to prove this conclusion false? Fine ... set up two amplifiers that deliver the same electrical signal ... according to full time-domain analysis, according to full frequency-domain analysis ... and demonstrate an observable, statistically-significant difference. One should note, however, that it's been tried many, many times ...

Wait ... what about reactive loads? Already included ... they will, or will not, impact the _frequency response_ of the amplifier(s) in question. If a significant, measurable difference is observed, then a sonic difference will also be possible. If the amplifier's output impedance is low enough that the reactive load presents no significant difference in _frequency response_, then the electrical signals presented to a loudspeaker will be the same. Can a sonic difference still be heard? Does the speaker "know" something OTHER than the voltage presented to it's terminals?

Wait ... what about heat dissipation? I'll give you two amps : the electrical outputs measure identically, but one is hotter then the other. How will the loudspeaker know the difference? Well, maybe the speaker's temperature is a bit higher cuz it's in close proximity to the warm amp ... 

Wait ... what about weight? Two amps have identical electrical outputs, but one amplifier weighs more than the other. Maybe it's gravitational field impacts the speaker differently ...

Wait .. what about listener fatigue? Again, missing the point. Amplifiers are ELECTRICAL. They are measured in the TIME DOMAIN, and/or FREQUENCY DOMAIN. If two amplifiers deliver the same signal, measured over TIME ... how will human hearing "fatigue" over one of them, but not the other? That's where that pesky "laboratory" comes in handy, what with it's nifty ability to logically separate variables vis-a-vis cause & effect ...


----------



## cubdenno (Nov 10, 2007)

Lycan,

I know you have written all this before in other similar posts, but Thank you again.


Same to Mark and DS!! 

I love reading this stuff!


----------



## lycan (Dec 20, 2009)

cajunner said:


> I very much want to agree with such common sense logical analysis, and I have to concede that electrically, there should be no difference between, but....
> 
> lol...
> 
> ...


I'll extend & elaborate, maybe wander around aimlessly for a bit ...

I've said that loudspeakers should be treated *differently*. Does that mean that loudspeakers operate beyond the realm of logic & science? OF COURSE NOT!! They are simply more COMPLEX. First of all, they present a NEW DIMENSION that's absent in electronic devices (that only "care about" voltage vs. time) ... that "new dimension" is SPACE. Speakers must be measured at different distances and angles for completeness ... electronic devices simply don't have this added dimension.

Furthermore, loudspeakers are the most non-linear elements in the reproduction chain ... by an order-of-magnitude (or two). This means that the complexities of distortion can almost never be ignored over the region of "normal operation", unlike power amplifiers & headunits. The Richard Clark test restricts operation of the amplifier to no (or low) distortion ... try to imagine a similar test for loudspeakers!

More random ramblings ...

What about jitter in digital devices? Jitter does NOT escape the scrutiny of math, logic and measurement ... i've tried to lay the foundation for such in the tutorials section  Jitter ABSOLUTELY falls under the category of "noise" in the classic parameters i've used to describe electrical devices. It's been MY CONTENTION, however, that jitter is a uniquely "weird" type of noise that will NOT be uncovered with a simple 1kHz measurement. It had no real history prior to the advent of digital audio in the early eighties. And lots of the early tests & analysis of jitter simply failed to recognize the "worst case" scenario ... of the jitter signals themselves, as well as the "carrier signals" modulated by the jitter (jitter is a _multiplicative_ noise, rather than an _additive_ noise, which makes it's observation more complicated ... and as such, it was something that many audio engineers were simply not equipped to deal with in the early days of digital audio). But the bottom line remains the same : it can be analyzed, measured & tested ... and if two devices measure the same (with jitter below an audible noise floor), they will sound the same. Perhaps, as DS-21 would contend, we've already achieved this plateau ... with ALL electronic noise sources, including that weird one, unique to digital audio, called jitter.

Back on-point: the most important thing to remember is the METHOD, rather than the CONCLUSIONS. Here's what i mean : 

This is an example of FAULTY reasoning : "I swapped two amps, and i KNOW they sounded different!!! Therefore, all this science stuff is just some crazy laboratory baloney. I know amps sound different !!!!"

A scientist would absolutely agree that simply swapping two amplifiers WILL result in different sound. First, check the gains : if the gains are not within 0.25dB of each other, you've just found the REASON why the amps sound different. After that, measure the FREQUENCY RESPONSE : you just might be surprised when you uncover the second REASON why amps can sound different. And so on, and so on ...

The laboratory IS the real world. It's not over the rainbow in oz. It's simply an environment where variables are ISOLATED, so that true cause & effect can be established. Without this guiding light, we're all wandering aimlessly in the dark ...


----------



## lycan (Dec 20, 2009)

cajunner said:


> okay, knee-jerk reactivity passing, let me try something:
> 
> "
> If two amplifiers deliver the same signal, measured over TIME ... how will human hearing "fatigue" over one of them, but not the other?
> ...


If two amplifiers have the same power, gain, frequency response, noise & distortion ... all measured over the same bandwidth of human hearing, all noise & distortion components below the threshold of audibility ... then these two gain blocks MUST be sonically "neutral". They will BOTH amplify that guitar decay identically, as far as human hearing bandwidth & dynamic range are concerned.

Is it *possible* for an amplifier to impart a "sonic signature" to a decaying guitar note? Sure ... if the amplifier introduces it's own dynamics (time constants, or poles) in the 20kHz bandwidth of human hearing, then it will impart it's own "decay signature"  But alas, it will not ... MUST not ... then have a flat frequency response from 20Hz to 20kHz  It's simply impossible to a have a flat frequency response (from 20Hz to 20kHz, magnitude & phase included) and still impart a "sonic signature" to a decaying guitar note.

And most people would conclude that they don't WANT their electronics to impart a sonic signature ... they would rather hear the guitar, thank you very much, rather than the amplifier


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> If two amplifiers have the same power, gain, frequency response, noise & distortion ... all measured over the same bandwidth of human hearing, all noise & distortion components below the threshold of audibility ... then these two gain blocks MUST be sonically "neutral". They will BOTH amplify that guitar decay identically, as far as human hearing bandwidth & dynamic range are concerned.
> 
> Is it *possible* for an amplifier to impart a "sonic signature" to a decaying guitar note? Sure ... if the amplifier introduces it's own dynamics (time constants, or poles) in the 20kHz bandwidth of human hearing, then it will impart it's own "decay signature"  But alas, it will not ... MUST not ... then have a flat frequency response from 20Hz to 20kHz  It's simply impossible to a have a flat frequency response (from 20Hz to 20kHz, magnitude & phase included) and still impart a "sonic signature" to a decaying guitar note.
> 
> And most people would conclude that they don't WANT their electronics to impart a sonic signature ... they would rather hear the guitar, thank you very much, rather than the amplifier


Okay, a few more questions for me on this subject:

1) So, is the real "reason" amps sound different because of the measurements we are given by the manufacturer and quality control within the amp manufacturing process? 

2) Also, what effect does headroom have? (i.e. Amp "a" is rated at 100x2 but has a 1000 watt power supply and amp "b" is rated at 100x2 but only has a 500 watt power supply - couldn't you level match both amps, but have a difference that is audible when driving the amp hard due to the extra headroom?) 

3) Will cheaper electrical parts act differently or out of tolerance under extreme stress or prolonged play time?

FYI, the Richard Clark challenge means nothing to me as he required you to pick 20/20 in order to prove a audible difference. You would fail at 19/20 and does anyone truly believe no audible difference exists at that point. Also, he will not divulge test scores of previous testers.


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> Okay, a few more questions for me on this subject:
> 
> 1) So, is the real "reason" amps sound different because of the measurements we are given by the manufacturer and quality control within the amp manufacturing process?


Nope. The _only_ reason amps can sound different is because they measure differently ... period. Of course, the measurements taken & reported (by the manufacture, or a third party) must be accurate & truthful. Regarding QC, a reputable manufacturer will either : test all amps from the production line to make sure each one meets target specs, or guarantee that all amps produced will meet target specs because all component variances are accommodated & allowed-for "by design".


> 2) Also, what effect does headroom have? (i.e. Amp "a" is rated at 100x2 but has a 1000 watt power supply and amp "b" is rated at 100x2 but only has a 500 watt power supply - couldn't you level match both amps, but have a difference that is audible when driving the amp hard due to the extra headroom?)


Mis-representing an amplifier's true power capability is nothing but marketing "specsmanship" ... and hopefully you can appreciate that such practice changes _nothing_, fundamentally, about the arguments i've presented. Does all logic, science and electrical theory suddenly become null & void if a manufacturer "describes" a 100 watt amplifier as a 50 watt amplifier?


> 3) Will cheaper electrical parts act differently or out of tolerance under extreme stress or prolonged play time?


Electronic _aging_ is a valid concern, for any electronic component. Typically measured over years. I would expect abnormally large failure rates, over years, to impact a manufacturer's reputation. But nonetheless, it has little bearing on the "sonic equivalence" of two electrical devices that are "electrically equivalent".


> FYI, the Richard Clark challenge means nothing to me as he required you to pick 20/20 in order to prove a audible difference. You would fail at 19/20 and does anyone truly believe no audible difference exists at that point. Also, he will not divulge test scores of previous testers.


What's so funny, to me, is that self-proclaimed audio gurus will go to _extraordinary_ measures and mental gymnastics to cling to a religious belief, rather than accept the simple, proven psychology that _knowing_ the brand name, ahead of time, _dramatically_ impacts how you "perceive" the sound!

"It's perfectly valid for me to know brand names in a non-blind test, and discard all measurements to establish equivalence ... but for the tester to expect 20/20 is complete ******** !!!"


----------



## tintbox (Oct 25, 2008)

"It's perfectly valid for me to know brand names in a non-blind test, and discard all measurements to establish equivalence ... but for the tester to expect 20/20 is complete ******** !!!"

So your not biased in any whey shape or form? You are a rare breed. Nothing wrong with it. Just typing.


----------



## lycan (Dec 20, 2009)

tintbox said:


> "It's perfectly valid for me to know brand names in a non-blind test, and discard all measurements to establish equivalence ... but for the tester to expect 20/20 is complete ******** !!!"
> 
> So your not biased in any whey shape or form? You are a rare breed. Nothing wrong with it. Just typing.


huh? i don't think you've understood what i wrote. The last statement (that you quoted) was a tongue-in-cheek, facetious "stab" at those who would choose to apply logic & science "selectively". I'll elaborate ...

It's funny for a subject to state the following :

"I don't beleeve in none of dis science mumbo-jumbo. Measurn **** and matching gains may be fine in ur fancy-pants lab, but in dis hear 'real world' it don't meen nuthn'. I know amps sound different, cuz i put a BallBlaster in my 96 civic and it blew da **** outa da HeadBanger in my buddies 92 camaro. Don't tell me about "isolatn' no variables" cuz dat don't mean **** in the real world. So what if I know da name brands bein tested, don't make no difference to me !!! Furthermore, a correct selection of 20/20 represents an abnormally high threshold in statistical expectations."


----------



## thehatedguy (May 4, 2007)

Someone please find the Bob Carver article/test that was done in Stereophile magazine (way before marketing ruled the pages). Read it. Digest it. Come back and reread what Jeff has said. See how they compare.

Stereophile: The Carver Challenge

carvermk2.com/docs/Carver%20Stereophile%20Challenge.pdf


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> Someone please find the Bob Carver article/test that was done in Stereophile magazine (way before marketing ruled the pages). Read it. Digest it. Come back and reread what Jeff has said. See how they compare.
> 
> Stereophile: The Carver Challenge
> 
> carvermk2.com/docs/Carver%20Stereophile%20Challenge.pdf


yep, that's a great article. EVERYONE should read it.

What is shocking and astonishing to me, is that the "audio reviewer gurus" know absolutely NOTHING about the most simple, basic principles of electronics and logic. These reviewers were in shock & awe ... _astonished_ and _stunned_ with disbelief ... over this simple principle:

*If two amplifiers deliver the SAME voltage to a loudspeaker, then the speaker has no choice but to sound the SAME. Furthermore ... that voltage can be measured, and adjusted at will.* 

Absolutely contrary to every religious principle they hold so dear, as guru-audiophile-reviewers.

I guarantee that, to this very day, they still don't understand this simple principle. "Surely," they are thinking, "there must be some symbiosis or gestalt or communion between an amplifier and a speaker that magically works outside the realm of voltage, outside the realm of electronic study, beyond the realm of logic ... ????"

LMFAO


----------



## Niebur3 (Jul 11, 2008)

Okay, read it. So, Carver was able to modify his amp to sound like a reference amp and that is supposed to convince me? Am I missing something.

So, do you, Lycan, believe that all Head Units sound the same? Are all D/A converters the same?


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> Okay, read it. So, Carver was able to modify his amp to sound like a reference amp and that is supposed to convince me? Am I missing something.


I hope that we _all_ now appreciate this:

*If two pieces of audio electronics are ELECTRICALLY the same, then they must be SONICALLY the same.*

It's OK ... like i said, most audiophile gurus would not understand this point.


> So, do you, Lycan, believe that all Head Units sound the same? Are all D/A converters the same?


Of course not. Two headunits with different volume settings will sound different. Two headunits with a different noise floor will sound different, as will two headunits with different frequency responses.

If two headunits are electrically indistinguishable, will they be sonically indistinguishable ???? Hmmmmmm .... i guess that depends on who you ask !!! LOL


----------



## lycan (Dec 20, 2009)

Time for me to ask a question :

*Niebur3, if i measure the outputs of two amplifiers (or headunits) and find that they are electrically "the same", can they still sound different?*

It's a simple question. And i'll quantify what i mean by "the same":

1. Gains within 0.25dB
2. Frequency responses (magnitude & phase) within 0.25dB over 20kHz
3. Noise floors both below -90dB, for all signals in the audio band
4. Distortion components below -80dB, for all signals in the audio band

All above points measured while driving the intended load.

Will these two pieces of audio electronics sound the same? I'll even make it multiple choice :

a. yes
b. no
c. not enough information given


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> Time for me to ask a question :
> 
> *Niebur3, if i measure the outputs of two amplifiers (or headunits) and find that they are electrically "the same", can they still sound different?*
> 
> ...


I love multiple choice . 
I don't know. I should answer B, but I understand you can "make" 2 amps sound that same as Carver did, but as a consumer buying off the shelf, is it really possible to buy 2 amps (1 high and and 1 much lower, but still competently designed) and yield identical sonic results?


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> I love multiple choice .
> I don't know. I should answer B, but I understand you can "make" 2 amps sound that same as Carver did, but as a consumer buying off the shelf, is it really possible to buy 2 amps (1 high and and 1 much lower, but still competently designed) and yield identical sonic results?


The correct answer is "a": if two pieces of audio electronics are _electronically_ the same, they must then be _sonically_ the same.

I can state this with complete certainty. There's no "gray area", or "wiggle room".

Not trying to be offensive, but that's what you _didn't_ get from the Carver article. What the Carver article exposed, was _not_ that two electronic devices could be made _electronically_ identical (to within -70dB, according to the article). The SHOCKING surprise from the Carver article was that well-known audio gurus fail to understand that, once two pieces of audio electronics are made to be _electrically_ indistinguishable, then it must follow ... as day follows night ... that these two pieces of electronics must then be _sonically_ indistinguishable. The gurus were stunned & shocked by this simple statement of logic  Their entire "belief system" was shaken, to it's very core, by this simple, logical conclusion.

And as i've said, to this day they still want to "believe" that there must be some "magic communion" between an amplifier and loudspeaker "beyond" electronics, "beyond" voltage ... indeed, "beyond" all logic.

Logic apparently has no role, in the mind of a self-proclaimed audio guru.


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> The correct answer is "a". I can state this with complete certainty. There's no "gray area", or "wiggle room".
> 
> Not trying to be offensive, but that's what you _didn't_ get from the Carver article. What the Carver article exposed, was _not_ that two electronic devices could be made _electronically_ identical (to within -70dB, according to the article). The SHOCKING surprise from the Carver article was that well-known audio gurus fail to understand that, once two pieces of audio electronics are made to be _electrically_ indistinguishable, then it must follow ... as day follows night ... that these two pieces of electronics must then be _sonically_ indistinguishable. The gurus were stunned & shocked by this simple statement of logic  Their entire "belief system" was shaken, to it's very core, by this simple, logical conclusion.
> 
> ...


No, I got that, but the way in which you worded your question above, the answer would then be "b". You asked "can they still sound different?...that is why I answered "b" for "no". 

But again, he had to modify the 1 amp to match the other perfectly in order for it to sound the same. Off the shelf, they sounded different because the specs were different. So, off the self, how hard is it really to find to amps that measure identical - even if their specs say they do?


----------



## DS-21 (Apr 16, 2005)

They don't have to measure "identically." Instruments are actually much more "revealing" than human hearing is, so two amps of the same design made on the same line for the same reseller will usually "measure differently" in some respect or another.

However, there are experimentally-established thresholds for "just noticeable differences" (JND's), and competently designed audio electronics of the same type (amps with similar output levels, digital sources, etc.) won't vary so much as to pass those JND thresholds and be audibly distinguishable from one another. Admittedly, that is a bit of a tautology, because if it varies so much in a given performance aspect it's probably not "competently designed" in the first place.


----------



## schmiddr2 (Aug 10, 2009)

lycan said:


> Nope. The _only_ reason amps can sound different is because they measure differently ... period.


This is how I am understanding this: Differences in output between various amps is read as an electrical measurement. Amps do sound different from one another, but one does not sound "muddy" or "sharp" compared to another for a magical reason (ex. warm sounding amp), it's the "power, gain, frequency response, noise & distortion" resulting from the amps intended transfer function (amps design of electrical components).

Is it poor design or cheap components or ??? that commonly cause possible amplifierr malfunction or failure? (Assuming it's not user error). Just trying to nail down something to differentiate an amplifiers perceived quality when this whole "amplifiers sound different" goes out the window.

Great information in this thread.


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> No, I got that, but the way in which you worded your question above, the answer would then be "b". You asked "can they still sound different?...that is why I answered "b" for "no".
> 
> But again, he had to modify the 1 amp to match the other perfectly in order for it to sound the same. Off the shelf, they sounded different because the specs were different. So, off the self, how hard is it really to find to amps that measure identical - even if their specs say they do?


The reference amplifier in the Carver article was a Conrad Johnson Premier 4. It's a vacuum tube amp (and a damn fine example of the breed, i might add). What this means is : that amp would NOT satisfy the "target specs" i suggested for electronic equivalence. Vacuum tube amps have a high-ish output impedance, which means a non-flat frequency response into reactive speaker loads. They tend to have high-ish harmonic distortion, no doubt significantly higher than the -70dB null Carver target (otherwise, Carver would not have needed to modify his amplifier's distortion to achieve the null). Vacuum tubes amps tend to also roll-off the bass response (discussed in the article), because it's damn hard to get good low-frequency performance out of the output transformers. What's the attraction, one might ask? Because many, including yours truly, find these distortions to be sonically _pleasing_  but i never confuse them with sonic accuracy.

So, yes ... 25 years ago, Bob Carver needed to perform several electronic tweaks on his solid-state amp to "match" the AUDIBLE electronic distortions of the big tube amp.

The phrase "competently designed" is not mine, and i'm avoiding it because i find it to be ambiguous. But i get DS-21's point, and i don't disagree. I also agree that audio engineers have determined "thresholds of audibility" for the kind of distortions & noises we're talking about.

So the bottom line is this : 25 years ago, Carver needed time & tools to match an amp whose distortions were most definitely NOT below the threshold of audibility. What does this mean for audio electronic devices today? Same, simple conclusion : if two devices are electrically indistinguishable, they will be sonically indistinguishable. There's two ways to get to "electrically indistinguishable" :

1. One device has very audible distortions, so the other must be tweaked/adjusted/modified to match. Once the match is achieved electrically, then a match is also achieved sonically.

2. Both devices have gain, power, frequency response, noise & distortion errors that are below well-known limits. One may be HUGELY below, and the other only SLIGHTLY below. These two devices will also be sonically indistinguishable. This is probably the category of "competently designed" ... but i'll still avoid that phrase


----------



## rain27 (Jan 15, 2009)

By the way, can anyone make sense of all the various upgrades that Tru Tech amps offer?

What differences in sound do different caps and op-amps make? 

Assuming these changes do alter the "sound signature" of the amp as Tru states, can these differences also be achieved with an eq or are these differences only achievable with hundreds of dollars in upgrades?

I've thought about purchasing some Tru amps, but cannot make sense of the upgrades and whether any of them are necessary.


----------



## DS-21 (Apr 16, 2005)

Cajunner, your test is inherently flawed, because you're assuming a priori that there are sonic differences. Before listening for _preference_, *difference* must first be established. One can't have a nonrandom "preference" between identically-sounding devices, but a small-n study may inadvertently lead to false positives!

But to your question (who would put whatever in), that's fine. There's nothing wrong with preferring something for legitimate reasons. It's just that with most audio electronics sonics just isn't a legitimate reason.

But I would think nobody would "feature" any amp in their ride. Why advertise to thieves that you have a system? Much, much better to hide everything from prying eyes.


----------



## DS-21 (Apr 16, 2005)

rain27 said:


> By the way, can anyone make sense of all the various upgrades that Tru Tech amps offer?


Yes. They're scams.

And one of the reasons I would avoid that particular amp reseller altogether.


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> gain, power, frequency response, noise or distortion


So, I would like to compare 2 amps with you (according to Mfr Specs):

McIntosh MCC404M:
Gain: Set using voltmeter at speaker terminals
Power: 100 x 4
Frequency Response: 20Hz - 20KHz (+0,-0.25dB)
Noise: >105dB a-weighted 1.5 volt
Distortion: .005% for 4ohm loads

JL Audio 600/4:
Gain: Set using voltmeter at speaker terminals
Power: 150 x 4
Frequency Response: 20Hz - 20kHz (does not state flat)
Noise: >110dB below rated power
Distortion: <.03 @ 4ohm per ch.

So, it may be hard not knowing how flat the frequency response is, but based on these specs, will these amps sound the same (if properly level matched) or will 1 sound better than the other and if so, why?


----------



## 3fish (Jul 12, 2009)

oh shoot! didn't see the cant tell the difference at 80mph...

Hey in my vehicle 70mph = 80db noise floor!


----------



## 3fish (Jul 12, 2009)

MarkZ said:


> I'm intrigued by the fact that when lycan says something, nobody gives him ****, but when DS-21 says the _same exact thing_ people jump up his ass.


'cuz lycan uses happy  and ds-21 pummels with a baseball bat then lays down a thick line of napalm, just for added measure...


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> So, I would like to compare 2 amps with you (according to Mfr Specs):
> 
> McIntosh MCC404M:
> Gain: Set using voltmeter at speaker terminals
> ...


Be careful ... what if your "4 ohm nominal" speaker has an impedance that actually drops close to 2 ohms over a certain frequency band? The McIntosh will double its power into this lower impedance, just like a voltage-source should  Will the JL double its power if the load impedance dips to 2 ohms? I don't know the answer.

But ... for a "well behaved" load that stays close to, or higher than, the 4-ohm load rating, these amps will be sonically indistinguishable (with gains set to within 0.25dB, and operating within the power limits of the less powerful amp, assuming no give-away turn-on pops, and assuming that the JL has a good balanced input stage like the McIntosh to cancel noise).

What answer were you expecting? A simple yes or no?


----------



## DS-21 (Apr 16, 2005)

Niebur3 said:


> So, it may be hard not knowing how flat the frequency response is, but based on these specs, will these amps sound the same (if properly level matched) or will 1 sound better than the other and if so, why?


There's no reason for any reasonable person of good faith to suspect they won't, unless you crank it loud enough that the McIntosh is driven into clipping. The Jello does have more power, after all.

However, one says "McIntosh" on the heatsink and might have meters on it while being much more expensive, so there are _plenty_ of reasons for an unreasonable person and/or a person of bad faith to think they'd sound different.


----------



## schmiddr2 (Aug 10, 2009)

cajunner said:


> hmm... gonna need a bigger boat.


Ha, majestic. Silly name for a good brand. Get a Grand Marquise; it's a boat.


----------



## MarkZ (Dec 5, 2005)

cajunner said:


> the amps will sound different if the power changes under load, that's already been discussed.
> 
> one amp will continue to double current under a decrease in resistance, the other will not.
> 
> ...


It has absolutely nothing to do with "higher quality components" or "tolerance levels." Higher quality components get you zilch when it comes to sonics. What higher quality components CAN potentially get you is greater tolerance to heat, voltage spikes, and maybe reduced failure rates.

I've said this before -- if you want to build a super-duper amp with low distortion and noise numbers and the flattest possible frequency response, it has very very little to do with the "quality" of the components you use. It has everything to do with the circuit design.


----------



## mosca (Oct 26, 2009)

FWIW, I'm living here this link to a Spanish website with some documented ABX tests Matrix-Hifi - Pruebas Ciegas

you can check the technical details for the ABX switching unit here ABX - Unidad de Conmutación Matrix

(links are Google-translated to English)


----------



## kyheng (Jan 31, 2007)

^So in other sense, you mean that if the circuit design is good, even using rejected components also sound compare to a not that good circuit design?


----------



## DS-21 (Apr 16, 2005)

cajunner said:


> I do assume, that differences will be established by preference, and I used the second study to verify that the first study wasn't a goof.


Well, you may need a two-stage study, but one cannot assume differences arguendo when it fact the whole issue is about the existence (or lack thereof) of sonic differences.



cajunner said:


> so, if preference is established, then differences will have to be assumed to exist.


There's no way to know in your hypothetical study if those "preferences" were based on actual differences or simply random, so you cannot assume on that basis that differences exist. 



mosca said:


> FWIW, I'm living here this link to a Spanish website with some documented ABX tests Matrix-Hifi - Pruebas Ciegas


Thanks for those data!

One test that tends to support my premise that boutique "high end" gear is often colored to the point that it can't reasonably be called high-fidelity (by either incompetent design or hacked assembly) is this one between a portable CD player and a DAC by one of the snottiest and most annoying firms in the so-called high end, Audio Note. A difference was found, and...preference favored the Discman!

And here's one comparing a glass-based amp to a sand-based amp. It appears the tube amp was well designed and properly maintained (poor design and lack of maintenance are the main reasons such amps "sound different" IME), because no difference was found.

And here's one on the order of the infamous DBT at Sunshine Stereo in Miami, where the late Steve Zipser was unable to reliably determine in his own room with his own system and his own program material whether he was listening to his own Pass Labs amps or an old Yamaha integrated amp (complete with extra preamp stage in the circuit!)!

At this point it's beyond amazing that there are still "true believers" in magical electronics. I can't escape the conclusion that such people are either acting in bad faith for their own pecuniary gain, or they're simply illiterate, or they've been stuck at a 2d grade reading level their whole lives.


----------



## mosca (Oct 26, 2009)

*DS-21*, all the people that participated in those tests don't worry anymore about sources and amps, they worry about speakers and physical room correction instead.

alas, you can throw this data to people and they will keep pullling out whatever arguments they can.

here's the detailed protocol for the tests Matrix Hi-fi - Metodología

their philosophy page is also quite interesting Matrix Hi-fi - Filosofía


----------



## mosca (Oct 26, 2009)

I hope this is not off topic, but here's an interesting and tangentially related blog post from Sean Olive (Harman International) Audio Musings by Sean Olive: Why Live-versus-Recorded Listening Tests Don't Work

here's what Edison thought about people:



> Second, Edison was the consummate audio salesman and was known to say, “People will hear what you tell them to hear” [2]. The expectations and perceptions of his listeners were manipulated before the test to produce a more predicable outcome. Audience members were given a concert program before his Tone Tests that clearly told them exactly what they would hear, how amazing it will sound, and what an appropriate response would be:
> 
> “Those who hear this test will realize fully for the first time how literally true it is that Mr. Edison has made possible the re-creation of the artist’s voice. No more exacting test could be made to demonstrate that the New Edison actually does re-create the voice of the artist than to play it side by side with the artist who made the records. This is the final proof. Close your eyes. See if you can distinguish the voice of the New Edison from that of the artist. Did you ever believe it possible to re-create a voice? Note that the voice of the artist and the voice of the Edison are indistinguishable” [emphasis is mine] [ 3].


----------



## MarkZ (Dec 5, 2005)

kyheng said:


> ^So in other sense, you mean that if the circuit design is good, even using rejected components also sound compare to a not that good circuit design?


For the most part, yes.


----------



## kyheng (Jan 31, 2007)

Any source to support this statement? You know if I were to big high end amps like the Mc, if found it to be using "good" circuit design but using rejected components, I'll feel cheated.


----------



## MarkZ (Dec 5, 2005)

I don't really know what you mean by "rejected".


----------



## kyheng (Jan 31, 2007)

^Well, as what I know from a friend that works for electronic company, when a factory makes capacitors, a certain standard must be met, like tolerence level, ESR and some others. Like Asus requires Panasonic to supply capacitors with tolerence level of +-3%, anything above that will be rejected. And such orders normally involved numbers of >1000pc.
When there's rejected components, where do they sell it? I pretty sure that tolerence level of +-3% is something a lot people will go for it. That's for a reputable company's requirements....
What if the rejected components with tolerence level of >10%? Is it really like what you said? I feel confused. Unless Asus is selling substandard motherboards, then I believe that your statement are right. Else, I let others to judge.


----------



## MarkZ (Dec 5, 2005)

I don't know. Who uses rejected components?? Completely unnecessary for a piece of electronics that fetches this kind of money.


----------



## kyheng (Jan 31, 2007)

Mark, basically I'm still waiting for your source that supports your statements which you claim that circuit design is more superior than components used. But I already knows that you won't be able to provide your source. By looking at how you ask the term "reject" and the latest reply, is known to everyone that you were to mislead us.
To answer your questions, lower end car audio or house audio will take such "rejected" components. Failed in industrail grade does not means failed for other usage.


----------



## cubdenno (Nov 10, 2007)

cajunner said:


> Could you win at Finals with Dual power?
> 
> hahaha...


You might if:
A. the noise floor is inaudible
B. You have it set that you don't clip it
C. You are able to hide the brand.

You think there is not a degree of skepticism and "brand racism...brandism?" out there. Especially on the competition circuit? When was the last time you heard of a new up and comer winning that was not part of team this or team that?


----------



## MarkZ (Dec 5, 2005)

kyheng said:


> Mark, basically I'm still waiting for your source that supports your statements which you claim that circuit design is more superior than components used. But I already knows that you won't be able to provide your source. By looking at how you ask the term "reject" and the latest reply, is known to everyone that you were to mislead us.


I have no idea what kind of "source" you're looking for. You mean, you want a citation out of a peer-reviewed journal? You want an explanation? You want references to electronics or amplifier design books or posts that will explain this stuff to you? I have no idea what you're looking for. I would have been more than willing to provide you _something_ if you clarified what it was you were talking about, but if you're gonna be a dick about it, then do your own damned homework.


----------



## Cruzer (Jul 16, 2010)

MarkZ said:


> I have no idea what kind of "source" you're looking for. You mean, you want a citation out of a peer-reviewed journal? You want an explanation? You want references to electronics or amplifier design books or posts that will explain this stuff to you? I have no idea what you're looking for. I would have been more than willing to provide you _something_ if you clarified what it was you were talking about, but if you're gonna be a dick about it, then do your own damned homework.


I dont think he is being fair anyways, if im understanding him correctly.

He is asking you if a lower end brand uses rejected parts, (out of spec parts)parts that might not project the same electrical signal as a high end amp that uses in spec parts, will the lower end still sound the same.

if the "rejected parts" are outside of the manufacturer's headroom for variance, then in my opinion yes it will sound different because its not doing its part to produce the same electrical signal as other amps.

if the "rejected parts" are still inside the variance manufacturers allow, then it should still sound the same because the electrical signal is still the same as other competing amps.

perhaps if the "rejected parts" affect an amps gain, power, frequency response, noise & distortion, then yes it will sound different.

im pretty new to car audio in general, especially in this detailed talk, so if im wrong, just ignore me. i already feel inferior to reply to this thread =/


----------



## trigg007 (Feb 24, 2010)

and Tannoys sound like garbage


----------



## kyheng (Jan 31, 2007)

^You see, I always like people when they don't read and try to understand properly what I said. Is my English that bad or someone are trying to be a screen dumb? I don't know.



MarkZ said:


> It has absolutely nothing to do with "higher quality components" or "tolerance levels." Higher quality components get you zilch when it comes to sonics. What higher quality components CAN potentially get you is greater tolerance to heat, voltage spikes, and maybe reduced failure rates.
> 
> I've said this before -- if you want to build a super-duper amp with low distortion and noise numbers and the flattest possible frequency response, it has very very little to do with the "quality" of the components you use. It has everything to do with the circuit design.


As you can see, I want some solid source to proof this statements. Why a manufacturer will make components with different tolerence levels and priced differently? If all the components sounds the same even with different tolerence level, then why people will source different tolerence level for different applications? 
Mark, do you have any source to support for your statements? I know you don't have but just for the sake of fun to ask again.


----------



## rexroadj (Oct 31, 2008)

No offense, its obvious you try, BUT......Yes, your english at times just flat out does not make any sense!


----------



## kyheng (Jan 31, 2007)

Thanks mate for your response. 
BTW Mark, just to add a bit before you try to drift my questions again, if all components with different tolerence level sounds the same or all capacitors sounds the same, why there's people spend money to get expensive components and modify their HUs or amps?


----------



## cubdenno (Nov 10, 2007)

kyheng said:


> Thanks mate for your response.
> BTW Mark, just to add a bit before you try to drift my questions again, if all components with different tolerence level sounds the same or all capacitors sounds the same, why there's people spend money to get expensive components and modify their HUs or amps?


He never said they ALL sound the same. Obviously some common sense must prevail when speaking broadly. When building something that is electronic in nature you circuit designer specs out what he needs component-wise. Then components are priced. At some point often, the accountants look at the wants of the circuit designer and say how about instead of resistor A which is a 1% and .10 a piece we use resistor b a 5%@ 2 cents a piece... The engineer replies "but but but that will take distortion from .004% to .04%"
the account would reply "Is that audible?'
engineer "no"
Accountant "OK then.. 5%'er it is."

As for the head unit upgrades the electrical signal rules should still apply. No one is saying that upgrading does nothing. I am sure in almost every case an upgrade could provide a measurable improvement. That does not mean it is audible.


----------



## kyheng (Jan 31, 2007)

^You got your point there, but how about capacitors? Tolerence level of 3% vs 10% are very big sometimes.
That's another reason why marketing, technical and account departments cannot work together. There's always conflicts between them. 
When talk about distortion levels, yeah, that 0.004% and 0.04% people may not able to hear them. But what about capacitors on the power supply? lower tolerence level is always better. I can put a +-20% which allows a greater spike, but this is not good for downstream components. 
A well design circuit is pointless if not using better components. just like Gigabyte high end motherboard, does it using lower grade components?


----------



## schmiddr2 (Aug 10, 2009)

kyheng said:


> A well design circuit is pointless if not using better components. just like Gigabyte high end motherboard, does it using lower grade components?


I think the higher grade components create less chance of equipment failure, but not audible sound quality differences.


----------



## kyheng (Jan 31, 2007)

^You think only? Why not ask Matt R? But more or less I'm in the same boat with you on this. Sometimes I also wondering is there any difference..... But when comparing MKT/MKP caps with normal bipolar caps I'm able to listen there's difference.
Or unless when we picking the capacitors, we test them out to get a matched pair. So when need to use capacitors, we may need to buy 4 capacitors or more to get a matched pair. Then with this way we may not able to hear there's difference.


----------



## kyheng (Jan 31, 2007)

^But I think I never mentioned on amp's class, right?


----------



## McDizzle (Jan 17, 2008)

Let me start off by saying I only read part of the first page. I just want to make a simple statement.

Let's make a hypothetical (which may actually be true). Let us stay with 100wx2 amp just to make things simple and make sound quality on a scale of 1-100

Sound quality of crappiest amp - 40 cost - $40

Sound quality of medium amp - 65 cost - $80

Sound quality of decently nice amp - 85 cost $200

Sound quality of way cool awesome amp 90 - cost $500

Sound quality of best amp in the world 100 - cost $2000


Now in this scenario I am setting up a basic principle that I have experienced throughout the years. At some point it is simply not cost effective to get better quality. Why pay $1500 for a minimal performance gain? Is the jump from $40 - $200 worth your money? Probably. Will you be able to notice a difference in quality? I don't think so, maybe a difference in general but not necessarily quality.

<rant>

The point I'm trying to make is STFU and buy the $200 amp  that should answer a lot of questions. And this is of course hypothetical, you can probably buy $200 crap somewhere I'm just making up numbers but the principle is the same.

Also, many "audiophiles" have a case of psychoacoustics when it comes to price/performance. Almost a way to justify a 2000 dollar purchase. "I spent $2000 so it DOES sound amazing and better than anything else"

</rant>

PS. Also note that the crappiest amp has quality of 40 because yes, between most amps the sound difference is generally tough to even hear. The crappy ones still do the job they were built to perform to a point....... until they pop


----------



## MarkZ (Dec 5, 2005)

kyheng, you want to know how I know? Because I understand how the circuits we're talking about work. This isn't a "source", this is knowledge. Learn about how to build and design an audio amplifier and you'll understand what I'm talking about. In the meantime, consider rereading lycan's post on the subject -- he explains it in greater detail than I do. Specifically, read where he talked about good circuit design nullifying the importance of precise component values. I know he's probably not a "source", as you call it, but maybe seeing a second engineer in this thread talking about this stuff might convince you that I'm not pulling this stuff out of my ass.

You want a book to read? Start with any number of electronics books (I prefer Horowitz and Hill's) that delve into common strategies in amplifier design -- learn how current sources, current mirrors, differential amplifiers, negative feedback, emitter-followers, darlington configurations, push-pull designs, and filters work. I think when you understand these things, you'll start to figure this out.

If you want to see the outcome of TESTS where you vary the values of these components and measure the distortion, noise, and frequency response of the output, then I strongly recommend Doug Self's amplifier design book, where he does exactly that. You'll need to first understand electronics though before you can truly appreciate his work. If you don't understand the topics in my previous paragraph, you won't understand his book.

If you want to ask me a more specific question, instead of throwing out vague accusations and insults, then go ahead and I'll do my best to answer it. But I'm not going to be helpful if you keep being insulting. That's all I have to say about that.


----------



## kyheng (Jan 31, 2007)

Ok, I just let you be the winner. Is it ok for you? I'm a bit reluctant already. I want a source but you ask me to read books? Man, that's a good way to answer questions, just like some jokers that knows nothing in my company but act like a pro. For people like me that won't design amps, is there a point to read? 
All I want is the source to proof your statements of different tolerence levels souns the same, is that really hard for you to give it out? I have no interest of your knowledge and won't accept statements like : "that's my experience, that's my knowledge and blah blah blah". The source I wanted is not from forum, I need source from website which is more appropiate. 
I always appreciate what people design and how they implement it. That's another reason why I got most of the Pioneer's service manuals(except JDM), from lowest end single din to higest end ODR.


----------



## kyheng (Jan 31, 2007)

McDizzle : Good comparisons...... If were to choose between that 5, I'll get 65 and 85 then compare them. But I'm not agree with you that "all amps sounds the same". Because the comparison is done subjectively. I've own 3 6 channels amp and I will say that the Pioneer's mini amp are better than JL's A6450 even the JL have 45W vs 22W. It is more transparent on certain parts especially on vocal. 
As for your rant, 2 terms can be use, "preception bias" and "expectation bias" is best to describe that.


----------



## trevordj (Feb 22, 2009)

You want a source (which he gave you at least two), but now you are saying you don't want to read? You don't want a forum source, but books are too difficult, so you want a website? 

Fail.


----------



## MarkZ (Dec 5, 2005)

kyheng said:


> Ok, I just let you be the winner. Is it ok for you? I'm a bit reluctant already. I want a source but you ask me to read books? Man, that's a good way to answer questions, just like some jokers that knows nothing in my company but act like a pro. For people like me that won't design amps, is there a point to readAll I want is the source to proof your statements of different tolerence levels souns the same, is that really hard for you to give it out? I have no interest of your knowledge and won't accept statements like : "that's my experience, that's my knowledge and blah blah blah". The source I wanted is not from forum, I need source from website which is more appropiate.
> I always appreciate what people design and how they implement it. That's another reason why I got most of the Pioneer's service manuals(except JDM), from lowest end single din to higest end ODR.


WTF? You ask for a source, I point to a post by lycan, I provide _book recommendations_ that would directly answer your question if you bothered to read them, and that's not good enough for you? Instead you just mock me? I really don't have the time for your nonsense anymore. There's a very special place on my ignore list for people who like to play games.


----------



## Niebur3 (Jul 11, 2008)

kyheng said:


> Ok, I just let you be the winner. Is it ok for you? I'm a bit reluctant already. I want a source but you ask me to read books? Man, that's a good way to answer questions, just like some jokers that knows nothing in my company but act like a pro. For people like me that won't design amps, is there a point to read?
> All I want is the source to proof your statements of different tolerence levels souns the same, is that really hard for you to give it out? I have no interest of your knowledge and won't accept statements like : "that's my experience, that's my knowledge and blah blah blah". The source I wanted is not from forum, I need source from website which is more appropiate.
> I always appreciate what people design and how they implement it. That's another reason why I got most of the Pioneer's service manuals(except JDM), from lowest end single din to higest end ODR.


Look, I started this thread to hopefully start a good discussion and get a poll count of people on this forum. I was the first to bring up the question of tolerances in parts used and if that makes a sonic difference and Lycan answered it. I believe there are many times when parts are used with greater tolerances and it will have a sonic difference, but what more do you want from Lycan and Markz about this? Markz and I have gone round and round about the subject of amps sounding different in the past and I know where he stands on it, but I would not insult him and try to make him prove something that he can't. The tolerances are built in to the design and if the manufacturer uses greater tolerances, if will show up if you bench the amps...something will be different/worse than the published specs.


----------



## cubdenno (Nov 10, 2007)

Niebur3 said:


> Look, I started this thread to hopefully start a good discussion and get a poll count of people on this forum. I was the first to bring up the question of tolerances in parts used and if that makes a sonic difference and Lycan answered it. I believe there are many times when parts are used with greater tolerances and it will have a sonic difference, but what more do you want from Lycan and Markz about this? Markz and I have gone round and round about the subject of amps sounding different in the past and I know where he stands on it, but I would not insult him and try to make him prove something that he can't. The tolerances are built in to the design and if the manufacturer uses greater tolerances, if will show up if you bench the amps...something will be different/worse than the published specs.


And adding to this the point remains that if you take two amps. One has 1% tolerance components and the other is using 5% tolerance components. If two amplifiers have the same power, gain, Noise, frequency response & distortion all measured over the same bandwidth of human hearing, all noise and distortion components below the threshold of audibility then they will reproduce the electrical signal the same.

And lower tolerance parts does not mean lesser quality. Most are made on the same assembly line. One of the product lines that I take care of deals with type B thermocouple wire. we utliize Super B from Johnson Matthey. This has the highest tolerance. The next level down is special B. Often times Special B has the same tolerance. it's just not certified as Super B. In my business we require that certification so that wee can show our customers the deviation possibility while using our products.


----------



## lycan (Dec 20, 2009)

well since i've got nothing better to do for a few minutes ...

Let's focus on ONE single component : the lowly AC coupling capacitor.

1. Component variance : as the cap value varies with temperature, or production variance, the -3dB AC coupling (or high-pass) frequency will vary (if you don't understand this, you have no business discussing electronic components ... period). So ... as MarkZ has been stating ... a good circuit designer will make sure that the expected variance (in production components, or temperature) will keep the -3dB AC coupling frequency well below some "target value" ... like 20Hz, for example. Therefore ... the FREQUENCY RESPONSE (remember that specification ????) will NOT be impacted over the audio band, by variation in the value of the AC coupling cap.

2. Voltage coefficient : we don't want capacitor values to change as the voltage across the cap changes ... this leads to harmonic distortion  But if we use a particularly non-linear (low-quality dielectric) capacitor as an AC coupling cap, we may see some HARMONIC DISTORTION (remember that specification ????) in the measured performance of the amplifier. However ... again, as MarkZ has been suggesting ... a good designer will keep that AC coupling frequency LOW enough, so that the voltage across the cap is very LOW as soon as frequency gets to that "target value" (e.g. 20Hz). So, once again, good circuit design practice helps mitigate any negative effects of non-ideal component performance.

In general, we should also recognize the very fundamental principle of negative feedback amplifiers (as established by Black in the late 20's, or more probably earlier by Blumlein) : as long as the gain of the "feedforward" section is high, the performance of the entire amplifier is defined by a few passive components in the "feedback" path. This allows the "active, gainy" section in the feedforward path to be : sloppy, ill-defined, drift with temperature and component tolerance, etc .... and yet it's impact on the overall performance is _minimal_, as long as the feedforward gain is high  It's the most fundamental aspect (virtue, in fact) of feedback amplifier design & performance, known for almost 100 years.

Where i might take small issue with MarkZ's otherwise intelligent comments  is that _sometimes_ good circuit design _can't_ accommodate (or "mask") bad component performance. A bad DAC comes to mind ... but DAC's haven't been a performance limiter in digital sources for probably 10 years (or more). So his points are generally valid.

I'll also agree with MarkZ, that the ignore list is a very valuable tool ...


----------



## MarkZ (Dec 5, 2005)

FWIW, there are electronic versions of both books I mentioned available.


----------



## Cruzer (Jul 16, 2010)

kyheng said:


> Ok, I just let you be the winner. Is it ok for you? I'm a bit reluctant already. I want a source but you ask me to read books? Man, that's a good way to answer questions, just like some jokers that knows nothing in my company but act like a pro. For people like me that won't design amps, is there a point to read?
> All I want is the source to proof your statements of different tolerence levels souns the same, is that really hard for you to give it out? I have no interest of your knowledge and won't accept statements like : "that's my experience, that's my knowledge and blah blah blah". The source I wanted is not from forum, I need source from website which is more appropiate.
> I always appreciate what people design and how they implement it. That's another reason why I got most of the Pioneer's service manuals(except JDM), from lowest end single din to higest end ODR.


Just look at it from a different perspective.

A car engine. They are made by lots of different people, lots of different parts, etc.

GM can make a 2.0 engine that has 100 hp gets 25 mpg.
Toyota can make a 2.0 engine, with completely different parts, still has 100 hp and gets 25 mpg.

Does that mean u get a different performance from the engines? No, they are the same.

Now, they do have differences in a car, gears, weight, etc.

You may drive a GM car with the 2.0 engine that is identical to toyota's engine and say hey this GM car is faster. But it wont be because of the engine. It will be because the gm car is lighter, different gears, etc.

They do the exact same thing, they provide power to the drive train.

Just like an amp produces the same electrical signal from amp to amp. Its other things that make them different like distortion, frequency response, etc. make the difference. not the signal


----------



## Oliver (Jun 25, 2007)

It all comes down to, what are you willing to pay for the amenities.


----------



## Niebur3 (Jul 11, 2008)

Now here is a really dumb question for this thread....

When comparing 2 amps, if 1 amp is a 100X2 @ 4ohm with a 1000 watt power supply and amp 2 is a 100X2 @ 4ohm with a 500 watt power supply, and I compare the 2 amps, will I notice a difference in a listening test? Is the rated power the proper spec to compare or do you need to know the size of the power supply inside?


----------



## kyheng (Jan 31, 2007)

Page 4, post 79. Try to read and understand. While our friend looks like 100% sure on his statements, I just need a solid proof to support that statement. Is it really that hard?
I don't care who is lycan or werewolf or MarkZ, who give a darn on that. I can always create extra 5 or 10 users and start saying "kyheng is vice president of XXX electronics factory which making this or that high grade components". 
People can always lies to others, but not equipment. Equipments won't lie.
Just take the power supply capacitors in an amp. If using the cap with lower tolerence levels, say +-3%, if each capacitor used is valued at 3000uf, that's +-90uf. If using the TL of +-20%, it will be +-600uf. Will it still no effect to other components? 
If everything like MarkZ said, then why a Tru Billet or Mc or Audison Thesis amp cost thousand of dollars? Do they use higher tolerence level components like cheaper brand does?


----------



## kyheng (Jan 31, 2007)

cajunner said:


> I think it may be that he's wanting a website explanation, an internet answer, because the books are harder to come by in Malaysia.
> 
> He can read whatever you can put in front of him, *online* but to source a book for an answer is like saying "go to electronics school if you want to know electronics" and really, it's not incumbent on you to tutor everyone who wants your input.


Bingo, you hit the jackpot, that was I want in the first place. The design book is jeust a reference, it may or may not applied to actual usage most of the time.


----------



## rain27 (Jan 15, 2009)

kyheng said:


> Page 4, post 79. Try to read and understand. While our friend looks like 100% sure on his statements, I just need a solid proof to support that statement. Is it really that hard?
> I don't care who is lycan or werewolf or MarkZ, who give a darn on that. I can always create extra 5 or 10 users and start saying "kyheng is vice president of XXX electronics factory which making this or that high grade components".
> People can always lies to others, but not equipment. Equipments won't lie.
> Just take the power supply capacitors in an amp. If using the cap with lower tolerence levels, say +-3%, if each capacitor used is valued at 3000uf, that's +-90uf. If using the TL of +-20%, it will be +-600uf. Will it still no effect to other components?
> If everything like MarkZ said, then why a Tru Billet or Mc or Audison Thesis amp cost thousand of dollars? Do they use higher tolerence level components like cheaper brand does?


Some amps cost thousands of dollars because people are willing to pay that much for certain brands. But that alone proves nothing.


----------



## kyheng (Jan 31, 2007)

^Yeah, maybe is like what you said, or maybe not. That's why I need to clairify this so I can file a law suit against those companies on "cheating" us.
That's a joke. And this will be the adavantages such company have. They can buy in bulk on each components and have few circuit designs. if they tested the components with lowest tolerence level, they use them for their high end lines. Failing that, they use it for lower end models. If still got balance and cannot fit to eaither 1 of their lines, they may discard it or sell to third party electronic components store. So sometimes we are not paying premium for the brand alone, the components price we pay also. 
make it this way, you buy 1 pc of capacitor, it may cost $1 because of the store's overhead, rental..... but if you buy in bulk of 1000pc, the cost maybe $100 or lesser. But do you use all the 1000pc for personal use?
Just like our PC RAM(Kingston for example), the matched pair are more expensive than normal standard RAMs even their spec all are the same. Marketing gimmick maybe some might say, or kingston really take time to do test on the selected pair.


----------



## thehatedguy (May 4, 2007)

Re power supplies...

The answer is...it depends. how close are you going to be to clipping? The one with the larger power supply could probably handle large transient dynamic swings better than the smaller one. Can you hear it? How loud are you listening and how close to clipping are you?

And Jeff picking on the AC coupling caps...poor guys. That's why they should be removed from the circuit...can't pick on what's not there .


----------



## Niebur3 (Jul 11, 2008)

cajunner said:


> sounds more like a different thread...
> 
> 
> but to answer, the point you are illustrating is probably the single biggest marketing tool amp manufacturers use to justify their circuit design in the higher cost brackets.
> ...


The reason it fits this thread IMO is because Lycan stated that "if two pieces of audio electronics have the same gain, power, frequency response, noise & distortion ... then what is the parameter by which they CAN sound different?"

So, based on the statement or Power, what is the determined power of the amp? 4 ohm, 2 ohm, power supply (for headroom) and what about clipping? Who doesn't listen to their music loud at least every once and a while and will an amp with a larger power supply that isn't clipping at musical peaks, when the other one is because of a much smaller power supply cause an audible difference even though the amp are rated at the same watts at say 4 ohm?


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> The reason it fits this thread IMO is because Lycan stated that "if two pieces of audio electronics have the same gain, power, frequency response, noise & distortion ... then what is the parameter by which they CAN sound different?"
> 
> So, based on the statement or Power, what is the determined power of the amp? 4 ohm, 2 ohm, power supply (for headroom) and what about clipping? Who doesn't listen to their music loud at least every once and a while and will an amp with a larger power supply that isn't clipping at musical peaks, when the other one is because of a much smaller power supply cause an audible difference even though the amp are rated at the same watts at say 4 ohm?


Let's say that i have two amplifiers:

1. Amplifier *A* that delivers 100 watts into 4 ohms, and 200 watts into 2 ohms (behaving like a true voltage source over this impedance range).

2. Amplifier *B* that delivers 100 watts into 4 ohms, but power-limits (or shuts down) at an impedance of 2 ohms.

If the loudspeaker of interest is indeed 4 ohms over the usable frequency range, we can expect these two amps to be sonically indistinguishable (assuming same gain, frequency response, noise & distortion).

If the loudspeaker of interest is "nominally" 4 ohms, but drops to 2 ohms over some of its usable frequency range ... can we still expect these two amps to be sonically indistinguishable?

If the answer is "no", does that disprove the hypothesis that: all amps which measure the same, will sound the same?

What does it say about the stupid hypothesis that : all amps sound the same?


----------



## trigg007 (Feb 24, 2010)

your premise is flawed...

Making the assumption that 4 variables will remain constant in real life is completely absurb and exactly why there can and will be differences in sound between amplifiers...


----------



## lycan (Dec 20, 2009)

trigg007 said:


> your premise is flawed...
> 
> Making the assumption that 4 variables will remain constant in real life is completely absurb and exactly why there can and will be differences in sound between amplifiers...


what "premise" ??

and exactly what 4 "variables" are being suggested to "remain constant" ??

If you're talking about gain, frequency response, noise & distortion ... you couldn't be more wrong. First, these are not "variables", they are measured specs. Second, it's trivial to get these to "remain constant" during an entire listening session ... if not the entire life of the product. Third, they don't even have to measure identically between products, if that's what you (erroneously) meant by "constant" ... the errors just have to measure, and remain, below the threshold of human hearing. This has already been discussed earlier in this very thread.

SO ... you couldn't have meant these specs. What "variables" are you talking about?

and which "life" am i referring to, if not the "real" one ??


----------



## trigg007 (Feb 24, 2010)

lycan said:


> Let's say that i have two amplifiers.....we can expect these two amps to be sonically indistinguishable (*assuming same gain, frequency response, noise & distortion*).


----------



## lycan (Dec 20, 2009)

trigg007 said:


>


that's what i thought ... you were wrong on at least three counts.


----------



## schmiddr2 (Aug 10, 2009)

trigg007 said:


> Making the assumption that 4 variables will remain constant in real life is completely absurb and exactly why there can and will be differences in sound between amplifiers...


And you read the whole thread?


----------



## lycan (Dec 20, 2009)

schmiddr2 said:


> And you read the whole thread?


clearly, he _hasn't_ read (or understood) the thread.


----------



## trigg007 (Feb 24, 2010)

lycan said:


> clearly, he _hasn't_ read (or *understood*) the thread.



We did...and we do...

Can we agree to disagree??


----------



## lycan (Dec 20, 2009)

trigg007 said:


> *We* did...and *we* do...
> 
> Can we agree to disagree??


how many of you are there? how many members use this username?

how many will i be agreeing to disagree with?


----------



## MarkZ (Dec 5, 2005)

trigg007 said:


>


You're absolutely right. Amplifiers will often sound different in practice because most people don't take the time to set the gain adjustments to match the previous setting when they swap out amps.

So what meaningful conclusion do we draw from this? That Brand X is better than Brand Y because in _your_ test Brand X's gain control was set more appropriately for the application? What happens when someone takes your recommendation but doesn't set the gain appropriately? They'll come back and say, "you were wrong! Brand X doesn't sound better than brand Y!"

This is why god created DIYMA. To dispel car audio land of that kind of nonsense. 

Instead, we're generally interested in buying equipment that we can make sound good after we learn how to install the equipment correctly and "tune" it (e.g. adjust the gain knob) to ideally suit our goals.

This is why it's probably better to rephrase the question. It shouldn't be, "do all amps sound the same?" It should be, "can all amps be made to sound the same without going to extraordinary measures?" I think most people correctly realize this. The thing that troubles me is that when some people answer "no" to the above question, they don't ask _WHY_. That's when they stop thinking, and ultimately end up making dumb purchases.


----------



## rommelrommel (Apr 11, 2007)

687 EELL Diamond Pigeon Sporting










687 Silver Pigeon V Mobilchoke®










Both spec'd with same barrels and same choke.

For their main purpose, which is putting projectiles downrange, are either of these guns superior? No. Put in a rest, and fired, they will both do exactly the same thing. 

Are they different? Obviously. Quality of materials and workmanship mainly. 

Is one worth more than the other? To people that value the materials, workmanship, rarity, yes. To those that only value projectiles downrange, no.

I can't believe that anyone is so stupid as to not understand that percieved value might be different between different items that serve the same function.

****, think about a fork. Is a stirling silver fork worth more than a stainless steel copy?


----------



## trigg007 (Feb 24, 2010)

MarkZ said:


> You're absolutely right. Amplifiers will often sound different in practice because most people don't take the time to set the gain adjustments to match the previous setting when they swap out amps.
> 
> So what meaningful conclusion do we draw from this? That Brand X is better than Brand Y because in _your_ test Brand X's gain control was set more appropriately for the application? What happens when someone takes your recommendation but doesn't set the gain appropriately? They'll come back and say, "you were wrong! Brand X doesn't sound better than brand Y!"
> 
> ...



Rock on (agreed!!!)


----------



## Cruzer (Jul 16, 2010)

rommelrommel said:


> 687 EELL Diamond Pigeon Sporting
> 
> 
> 
> ...


x2 i did the same thing except i used car engines. so long as the product lives up to its specs, no difference.


----------



## Niebur3 (Jul 11, 2008)

MarkZ said:


> You're absolutely right. Amplifiers will often sound different in practice because most people don't take the time to set the gain adjustments to match the previous setting when they swap out amps.
> 
> So what meaningful conclusion do we draw from this? That Brand X is better than Brand Y because in _your_ test Brand X's gain control was set more appropriately for the application? What happens when someone takes your recommendation but doesn't set the gain appropriately? They'll come back and say, "you were wrong! Brand X doesn't sound better than brand Y!"
> 
> ...


Not exactly! Again, what about the amp with the massive power supply vs the amp with the much smaller power supply? 




lycan said:


> Let's say that i have two amplifiers:
> 
> 1. Amplifier *A* that delivers 100 watts into 4 ohms, and 200 watts into 2 ohms (behaving like a true voltage source over this impedance range).
> 
> ...


Find me 2 amps that measure (power, frequency response, noise and distortion) the exact same (within the threshold of human hearing) in the real world (not published manufacturer specs) that have the same exact size power supply and type of power supply (regulated/unregulated) and I will agree when level matched (properly within .25dB) they "should" sound identical. Now find me those 2 amps


----------



## schmiddr2 (Aug 10, 2009)

Niebur3 said:


> Find me 2 amps that measure (power, frequency response, noise and distortion) the exact same (within the threshold of human hearing) in the real world (not published manufacturer specs) that have the same exact size power supply and type of power supply (regulated/unregulated) and I will agree when level matched (properly within .25dB) they "should" sound identical. Now find me those 2 amps


That is not the point. The special sounds people think they hear between various amplifiers is usually power output and gain. An amp does not make sound warm or smooth or whatever.

Even 2 similarly powerful amps (not exact), with the output set to the similar levels, will sound damn near identical. Assuming the amp was built competently and the frequency response, noise & distortion in line with that.

This is just from what I've gathered in this thread. I'm no engineer like some people here.


----------



## Cruzer (Jul 16, 2010)

Niebur3 said:


> Find me 2 amps that measure (power, frequency response, noise and distortion) the exact same (within the threshold of human hearing) in the real world (not published manufacturer specs) that have the same exact size power supply and type of power supply (regulated/unregulated) and I will agree when level matched (properly within .25dB) they "should" sound identical. Now find me those 2 amps


like the above, im no engineer, but i think the main thing this thread means is this.

mb quart 1500 costs like $220
Rockford Fosgate Power T1500 $400+

so long as the mb quart is built decent, there should not be any audible difference @1ohm both supplying a true 1500 watts.

but because people probably believe more in rockford amps vs mb quart amps, when they test both in real life, they will say the rockford sounds better. mostly because its in their head, they like rockford better, its going to pretty much trick them into believing it. When in reality both are putting the same signal to speakers, sub, etc. and indeed no audible difference.

now say u go with a Lanzar MAXP1200 that says it does [email protected] and costs a whole 99$.

u plug that up vs either the mb quart or rockford, its gonna be huge.

i personally had a friend buy that amp... he could not get his sub to sound right at all. laugh, go figure.


----------



## gijoe (Mar 25, 2008)

Lycan is a smart man and obviously doesn't need my backup, but i feel like some of you are missing what he is saying, maybe he's talking over your head.

He isn't claiming that amps all sound the same. He's stating the fact that IF they measure the same, they WILL sound the same.

Lycan isn't claiming that amps generally measure the same. He knows that some amps are designed with with a less than flat FR intentionally, he knows that tube amps have high distortion, he's simply stating that these are the things that make an amp sound different. If the gain, fr, noise and distortion measure the same, the amps will sound the same.

I didn't see ANYWHERE where Lycan claimed it's easy to find two amps that measure the same...

The point is amps do sound different, but if you take 2 typical amps with noise and distortion below our threshold of hearing (which most "competently" designed amps/hu's will be) then adjusting the gain and fr between two amps is pretty easy. Two amps won't necessarily sound the same out of the box, but it's relatively easy to get them to.


----------



## Hillbilly SQ (Jan 26, 2007)

I snuggle with my warm amps at night


----------



## lycan (Dec 20, 2009)

schmiddr2 said:


> That is not the point. The special sounds people think they hear between various amplifiers is usually power output and gain. An amp does not make sound warm or smooth or whatever.
> 
> Even 2 similarly powerful amps (not exact), with the output set to the similar levels, will sound damn near identical. Assuming the amp was built competently and the frequency response, noise & distortion in line with that.
> 
> This is just from what I've gathered in this thread. I'm no engineer like some people here.


THANK YOU THANK YOU THANK YOU !!!!!!

All those "wonderful sonic magix" attributed to amplifiers can _all_ be traced & attributed to very familiar _electrical_ specifications (an amplifier is, after all, an _electrical_ appliance ... nothing more). If those specs are equal (to within the known limits of human hearing), the amplifiers have *no choice* but to "sound" the same.

Amplifiers are designed, characterized and tested on the production line according to their _electrical_ performance ... why would it be otherwise, for a device whose inputs & outputs are electrical? So why expect a "different" sound from devices that are electrically indistinguishable?

We have a winner


----------



## lycan (Dec 20, 2009)

gijoe said:


> Lycan is a smart man and obviously doesn't need my backup, but i feel like some of you are missing what he is saying, maybe he's talking over your head.
> 
> He isn't claiming that amps all sound the same. He's stating the fact that IF they measure the same, they WILL sound the same.
> 
> ...


Holy cow ... two winners in the SAME evening !!!!

Thank you THANK YOU THANK YOU !!!

Why is this so hard to understand? Why do we all so _desperately_ want to believe in some magic amplifier attributes beyond electrical performance, some magical communion between an amplifier and its electrical load that defies all logic and electrical theory?

It doesn't detract from the magic of audio! Stop looking for magic in the glass that protects the Mona Lisa !!!


----------



## lycan (Dec 20, 2009)

lycan said:


> Let's say that i have two amplifiers:
> 
> 1. Amplifier *A* that delivers 100 watts into 4 ohms, and 200 watts into 2 ohms (behaving like a true voltage source over this impedance range).
> 
> ...


However ... we would all do well to understand the answers to these questions 

Please indulge me, and ponder these questions ...


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> Now find me those 2 amps


Pick two.


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> Holy cow ... two winners in the SAME evening !!!!
> 
> Thank you THANK YOU THANK YOU !!!
> 
> ...


I like how you explain things, the point I am trying to get at is two many people who say "all amps sound the same" seems to not understand the basis in which they need to match in order to sound the same. It is too loosely thrown around "they all sound the same" (which, by the way, you have never said). 

I will absolutely agree that if they measure the same, they must sound the same!

But to find 2 amps of different brands off the self that measure identical enough with everything you have explained and the whole power supply variable, I just think it would be damn hard to find. 

The differences may be subtle and slight and some people may not care or even be able to hear due to noise floor in vehicle, speakers, installation, tuning, etc. 

This may be completely off base, but it seems to me that the more of the expensive amps have larger power supplies, which could/would account for the sound difference - they also tend to be very underrated - probably on purpose so they do sound different. As far as differences between OpAmps, caps, etc., I have had so many people tell me that they DO make a difference, that I have always believed some in their "magic", but not without some skepticism that over the last year especially has turned to "where is the proof".

Lycan, thanks again for your contribution to this thread. I think another point would be to worry more about installation, tuning, speakers, etc. that can make a huge difference in sound and if you can perfect all that and can afford it, buy whatever the hell amps you want that make you feel good. People do buy Ferrari's over Corvette's for a reason.


----------



## Niebur3 (Jul 11, 2008)

MarkZ said:


> Pick two.


I asked you first


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> I asked you first


It's incredibly simple and inexpensive to produce an amplifier that is perfect (to our crappy sensory abilities, at least). Obviously, two perfect amplifiers would be indistinguishable. If the manufacturer can't achieve this, then they're either intentionally doing it, or are too cheap to scrap together a respectable board, connections that won't fall apart, and buy discrete components.

In car audio, most differences that are substantial enough to be audible come from undefeatable signal processing (crossovers, boosts, etc) or noise issues. There are tons and tons of amps that don't have those problems. Which is why I said pick two. I was just hoping like hell you weren't going to pick one of the weird ones. 

Anyway, the consequence of lycan's position is that we can make a set of measurements and be able to predict fairly easily whether two amps will sound the same. My point is that it's not as rare as you think.

Edit: And I still don't get the "real world" stuff. All you really have to worry about is matching gains and making sure internal processing is turned off (or matched). Yes, these can have influences, but technically, neither the gain control nor the internal processing is part of an "amplifier" per se, even though it shares the same box.


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> I like how you explain things, the point I am trying to get at is two many people who say "all amps sound the same" seems to not understand the basis in which they need to match in order to sound the same. It is too loosely thrown around "they all sound the same" (which, by the way, you have never said).
> 
> I will absolutely agree that if they measure the same, they must sound the same!
> 
> ...


some people buy corvettes _and_ Ferraris  

Yes, amplifiers can & do sound different. But it's perfectly reasonable to understand that, given the state of electronic circuitry, it's not hard (like it was 50 years ago) to build an amplifier whose errors in gain, power, frequency response, noise & distortion are all well below the limits of human hearing (this, i suspect, is behind the "competently designed" phrase). 

So, if nothing else comes of this discussion, consider this when comparing ANY two amplifiers : there's a well-known list of things that can CAUSE one amplifer to sound different than another. These are :

1. Gain difference by 0.25dB or more
2. Frequency response errors of 0.25dB or more
3. Power
4. Noise & distortion greater than, say, -80dB.
5. The psychology of knowing which brand name you're listening to

So consider these KNOWN things that cause amps to "sound" different. Wouldn't you like to know which one is causing the sonic difference you "heard"? *Most importantly, how much are you willing to PAY for a sonic difference due to one of these parameters?*

Trust me ... audio salesmen know these effects VERY well. Crank the gain on the brand you want to move by a quarter dB or so, crank the brightness on the TV brand you want to move ... all well known tricks.

You think you hear a difference? *ask WHY !!!!!* Hell, MEASURE the outputs of the two amps with an AC voltmeter at a few different frequencies  Fear not, you won't "spoil" the amplifier magic by putting a voltmeter across its output terminals.

Then, ask how much you're willing to pay for that tweak of the gain knob, or that slight bump in midrange frequency response ...


----------



## subwoofery (Nov 9, 2008)

Cruzer said:


> Just look at it from a different perspective.
> 
> A car engine. They are made by lots of different people, lots of different parts, etc.
> 
> ...


What happens if the GM and the Toyota cars had the same weight, same power and 25mpg? Same gears but one would still BE faster... Humm... What could that be?... 

TORQUE... Some amps have more torque (SQ) than others.  

Kelvin


----------



## msmith (Nov 27, 2007)

Lycan,

As you know, most amplifier bench tests are done with steady state supply voltage, steady state signals and purely resistive loads. It is possible for two amplifiers to test identically (theoretically) under the above conditions, yet test differently when measured with dynamic signals, reactive loads and a "squishy" supply voltage. 

This, of course, does not negate your basic premise... it simply points out that the typical "bench test" may not be complete and conclusive. In simple terms, to paraphrase Paul Klipsch: "If it measures the same and sounds different, you're not measuring the right thing."


----------



## SoundChaser (Apr 3, 2009)

lycan said:


> some people buy corvettes _and_ Ferraris
> 
> Yes, amplifiers can & do sound different. But it's perfectly reasonable to understand that, given the state of electronic circuitry, it's not hard (like it was 50 years ago) to build an amplifier whose errors in gain, power, frequency response, noise & distortion are all well below the limits of human hearing (this, i suspect, is behind the "competently designed" phrase).
> 
> ...


I don’t follow how the gain difference would skew the comparative results of 2 amplifiers.

1 amp reaches its full potential @ ½ volume off the head unit. The other amp reaches the same SPL level @ ¾ volume off the head unit.

What’s the difference?


----------



## lycan (Dec 20, 2009)

SoundChaser said:


> I don’t follow how the gain difference would skew the comparative results of 2 amplifiers.
> 
> 1 amp reaches its full potential @ ½ volume off the head unit. The other amp reaches the same SPL level @ ¾ volume off the head unit.
> 
> What’s the difference?


small gain differences (fraction of a dB) are often "perceived" by human hearing as differences in "quality", rather than differences in "volume". Same can be said for small differences in brightness in TV screens 

Oh dear, how oh how can we _possibly_ eliminate that difference when comparing two amplifiers? All hope is lost! We have no choice but to accept the mysteries of SQ ...

How much will YOU pay for that small tweak of the gain knob? How can one possibly determine if that's the cause of the difference heard ????????


----------



## lycan (Dec 20, 2009)

cajunner said:


> I'd like to believe that someone who has been listening to say, a Milbert tube amp, could easily pick his amp out of a line-up, but since reading this thread I'm not so sure.


  

If you had read and _understood_ this thread  then you would readily accept that a person could _easily_ pick out his Milbert tube amp in an amplifier comparison ... but the reason *WHY* is because of the tube amplifier's gain, power, frequency response (probably), noise or distortion (equally probable) 

I'll repeat it for the miliionth time : All amps do NOT sound the same. I can pull two amps from the same damn production line, and set their gains or crossovers different, and i promise they WILL sound different. *It's astonishing to me that nobody understands this.*

Seems to me, everyone wants to put themselves into one of two EXTREME categories : either all amps sound mysteriously different, for reasons beyond all logic and understanding .... or else, at the other extreme end of the spectrum, any two amps under _any_ circumstances (wildly different gains, completely different crossover settings, etc) will sound exactly the same.

Are these _really_ the only two categories? All amps are EXACTLY the same *no matter what*, OR it's impossible for any two amps to be sonically indistinguishable *no matter what*?

That's what this debate _always_ degrades into


----------



## DS-21 (Apr 16, 2005)

cajunner said:


> To be honest, I don't know too many people who would agree to have their Zuki/Genesis/Audison/Sinfoni/Luxman/Milbert/McIntosh/F1 Alpine/ODR/XES etc., amplifier tested against a Boss or Legacy in a double blind study.


Why not? 

A now-dead Miami audio dealer once agreed to blindly compare his own Pass Labs amp, which costs a helluva lot more than any piddly car-fi boutique crap, to a cheap Yamaha integrated.

I've gotten people to compare Meridian gear (again, more expensive than pretty much anything available for car-fi) against mass-market (two-figure pricetag) gear. I've compared my own Classe gear (see a trend) against much cheaper gear.

So, are you saying that people who buy boutique car-fi gear on the illusory grounds that it "sounds better" are exceptionally deluded even by the moronic standards of "high end" home audio? 

Or just that that people who buy boutique car-fi gear on the illusory grounds that it "sounds better" are too poor for their little brains to withstand knowing that they might have eaten peanut butter and ramen for a month for no sonic reason?




lycan said:


> Seems to me, everyone wants to put themselves into one of two EXTREME categories : either all amps sound mysteriously different, for reasons beyond all logic and understanding .... or else, at the other extreme end of the spectrum, any two amps under _any_ circumstances (wildly different gains, completely different crossover settings, etc) will sound exactly the same.


Sorry, but that sounds a little bit like Republicans screaming that Obama is a "socialist." As in that debate, there is one extreme position that is apparently still widely-held despite being easy to disprove. (Well, I suppose there are still people who think the earth is 6000 years old, too...) And there is a second position that only exists in the collective imagination of those aforementioned extremists, but not in real life. The only things that claiming said second position exists do is demonstrate to sane, reasonable people that the holders of the former position are 
a) utterly decoupled from reality.
b) too intellectually unsophisticated to understand the difference between *questions of fact* (does x sound different from y?) and *matters of opinion/preference.*

Nobody here's articulated an argument anything remotely like the your illusory "other extreme end." And, in fact, I've never heard anyone say things like level and FR are inaudible in controlled listening. Obviously, were someone to articulate that position, rational people who deride the advocate as being just as brainless and/or deaf as the "magic voodoo sonic differences" crowd.


----------



## lycan (Dec 20, 2009)

DS-21 said:


> Nobody here's articulated an argument anything remotely like the your illusory "other extreme end." And, in fact, I've never heard anyone say things like level and FR are inaudible in controlled listening. Obviously, were someone to articulate that position, rational people who deride the advocate as being just as brainless and/or deaf as the "magic voodoo sonic differences" crowd.


I agree ... the extreme position has not been articulated, but it certainly has been implied. Here's a "version" of the same position :

I'll take two amplifiers from the same production line. I'll make sure they are level matched at 1kHz. But the crossover settings in one amp are wildly different than the other amp : one amp is high-passed at 50Hz, the other is high-passed at 200Hz (and yes, the crossover circuitry is, strictly speaking, in the pre-amp section ... exactly where the gain circuitry is, in most car amps). Surely, they "sound" different. Which one is the incompetently designed amp?

A stupid, trivial, meaningless example? Not to this crowd! Because there's a thought process that many will NOT follow. "Well, duh lycan ... of course we mean the crossovers must be _the same_ too. Or else the frequency responses will be wildly different !!". And i'll respond by saying : How CLOSE must they be? If you were to put MONEY on the line ... which you do, when you make a purchase decision .... how will you determine if the frequency responses are "close enough" for a valid comparison? Will you look at the approximate position of the detent on the crossover knob, or ... will you MEASURE the frequency responses, according to a target spec of, say, a fraction of a dB?

Disable the crossovers, you say? And that's enough to convince you that the frequency responses are within a fraction of a dB ... if there's real money on the line?

I promise you ... most of the audience _still_ doesn't get that the fundamental proposition here is NOT that all amps sound the same, but rather that all amps which _measure_ the same, will sound the same ... and that we can use a small set of well-established *electrical* parameters or specs to completely & thoroughly characterize any & all *sonic* attributes, just like every manufacturer does when they design & test these appliances in large volume. 

Most don't even understand the difference 

EDIT : and we haven't even _begun_ to explore the point i tried to make earlier, and that Manville started to elaborate on ... how do we comprehend a loudspeaker's _reactive_ impedance in an amplifier comparison, when most tests & specs are made with a simpler _resistive_ load? Two amplifiers that spec, and therefore sound, identical with a 4 ohm load that's almost purely resistive, may in fact _not_ spec, nor sound, identical with a load that's "nominally" 4 ohms, but has substantial reactive variance. Such a proposition would surely confound the "all amps sound the same" thesis, but not necessarily the "all amps that measure the same, will sound the same" proposition.


----------



## DS-21 (Apr 16, 2005)

lycan said:


> I'll take two amplifiers from the same production line. I'll make sure they are level matched at 1kHz. But the crossover settings in one amp are wildly different than the other amp : one amp is high-passed at 50Hz, the other is high-passed at 200Hz (and yes, the crossover circuitry is, strictly speaking, in the pre-amp section ... exactly where the gain circuitry is, in most car amps). Surely, they "sound" different. Which one is the incompetently designed amp?


I'm confused why you're bringing crossover settings into the argument. If they're defeatable, then it's not relevant to a discussion of sonic differences.

But let's assume the settings are made at the factory and non-defeatable. Then the answer is:

Both, if they're both impliedly intended for full-range use.

The latter, if they're both expressly intended just for use driving mains in a "typical" system (60-150 Hz highpass).

Neither, if they're expressly designed only to drive tweeters (1KHz and up, let's say).



lycan said:


> And i'll respond by saying : How CLOSE must they be? If you were to put MONEY on the line ... which you do, when you make a purchase decision .... how will you determine if the frequency responses are "close enough" for a valid comparison? Will you look at the approximate position of the detent on the crossover knob, or ... will you MEASURE the frequency responses, according to a target spec of, say, a fraction of a dB?
> 
> Disable the crossovers, you say? And that's enough to convince you that the frequency responses are within a fraction of a dB ... if there's real money on the line?


If there's purchase money on the line, a reasonable person isn't too worried about it. Even if the level variations are slightly audible with some program material, a well-designed system will use signal processing that can fix such issues anyway.

If it's an "amp challenge" I would spot-measure voltage at a few frequencies. In one I recently did (which, for the record, netted me an Arc KS125.4 Mini and a couple hundred bucks for Pakistani flood relief in the person's own lorry with his own speakers and own choice of program material he felt had revealed differences in sighted listening) I just measured voltage off of since waves at 50, 1k, and 10k Hz and matched gains. That was sufficient for the amp to be sonically indistinguishable.



lycan said:


> EDIT : and we haven't even _begun_ to explore the point i tried to make earlier, and that Manville started to elaborate on ... how do we comprehend a loudspeaker's _reactive_ impedance in an amplifier comparison, when most tests & specs are made with a simpler _resistive_ load? Two amplifiers that spec, and therefore sound, identical with a 4 ohm load that's almost purely resistive, may in fact _not_ spec, nor sound, identical with a load that's "nominally" 4 ohms, but has substantial reactive variance. Such a proposition would surely confound the "all amps sound the same" thesis, but not necessarily the "all amps that measure the same, will sound the same" proposition.


I dismiss the point out of hand, because *it has never been shown to be meritorious in a controlled listening test.* 

It's all just hand-waving until/unless someone can point to a positive identification in a controlled same/different subjective listening evaluation.

I think you would agree that a Yamaha integrated amp with a standard AB amp circuit probably acts somewhat differently into reactive loads than a tweaky single-ended solid state amp, right? Such as, say, the old Pass Aleph series. Well, we know how that went!


----------



## rommelrommel (Apr 11, 2007)

lycan said:


> EDIT : and we haven't even _begun_ to explore the point i tried to make earlier, and that Manville started to elaborate on ... how do we comprehend a loudspeaker's _reactive_ impedance in an amplifier comparison, when most tests & specs are made with a simpler _resistive_ load? Two amplifiers that spec, and therefore sound, identical with a 4 ohm load that's almost purely resistive, may in fact _not_ spec, nor sound, identical with a load that's "nominally" 4 ohms, but has substantial reactive variance. Such a proposition would surely confound the "all amps sound the same" thesis, but not necessarily the "all amps that measure the same, will sound the same" proposition.


This is what I really want to hear about. I believe that any differences are measurable, but that there are likely differences. If there is an impendance spike in the passband and two amplifiers handle impedance spikes differently, could it not produce an audible difference? Or does competent design account for this?


----------



## lycan (Dec 20, 2009)

rommelrommel said:


> This is what I really want to hear about. I believe that any differences are measurable, but that there are likely differences. If there is an impendance spike in the passband and two amplifiers handle impedance spikes differently, could it not produce an audible difference? Or does competent design account for this?


More likely, the problem would be an impedance "dip" ... amps must work harder into lower impedance loads.

I'll allow for the possibility, as does Manville (i think). Whether or not it's ever been uncovered in a finite sample size of controlled listening tests is irrelevant ... it's certainly possible, and logical, based on well-established electronic theory and known listening thresholds. An amp which shuts down, goes unstable, or current-limits, into a 2-ohm load (while being perfectly happy with a 4-ohm load), would be _expected_ to behave "differently" while driving a speaker whose reactive impedance dips to 2-ohms ... as compared to an amplifier whose power simply doubles into 2-ohms. To expect otherwise, is irrational. Therefore, i'll allow for the possibility ... even if i can't point to a specific listening test that revealed the principle.

The key point for me, as it has always been, is this : if a difference in the "*sound*" of electronic equipment can be heard, then that difference can be *electrically* measured. And it follows, then, that if two pieces of electronic equipment are *electrically* indistinguishable (into the same load!), they must be *sonically* indistinguishable. This is simple "if p, then q" logic ... nothing more.


----------



## DS-21 (Apr 16, 2005)

lycan said:


> I'll allow for the possibility, as does Manville (i think). Whether or not it's ever been uncovered in a finite sample size of controlled listening tests is irrelevant ...


Why? Lots of things are theoretically possible, but don't actually happen.

When it comes to audibility, the only thing that's important is, well, establishing audibility. There can be no question of preference, relative fidelity to the source material, etc., unless the threshold determination that there is an audible difference has been affirmatively made.

The only way to do that is to isolate the variable in question and listen to see if a difference can be actually established to a reasonable degree of statistical significance. 

Unless we're talking about a measured property that has already been shown to be audible in such circumstances, anything less is just mental masturbation.



lycan said:


> The key point for me, as it has always been, is this : if a difference in the "*sound*" of electronic equipment can be heard, then that difference can be *electrically* measured.


We're in agreement on one crucial point: the priority of sound (is there an audible difference in controlled listening?) over all other factors. Where we disagree is on what follows. I say that it follows logically to say that if there's no audible difference established, there's no need to measure esoteric things such as output into weird loads and so on. Everything must stem from that threshold determination of audibility.


----------



## lycan (Dec 20, 2009)

DS-21 said:


> Why? Lots of things are theoretically possible, but don't actually happen.
> 
> When it comes to audibility, the only thing that's important is, well, establishing audibility. There can be no question of preference, relative fidelity to the source material, etc., unless the threshold determination that there is an audible difference has been affirmatively made.
> 
> ...


I know what you're saying, but you can have a theory that allows for, even expects, and "event". Now perhaps, at this point in time, the "event" has not yet been observed. What does that mean? Not much, really. It doesn't disprove the theory ... the theory simply remains open to the possibility. That's all i'm really saying. Well, i'm actually saying something more ... i'm saying that if a difference is really _heard_ in a controlled test, i'm hoping to *point to* some simple _electrical_ tests that can help uncover the simple question : why?

There are some _extreme_ examples that come to mind in other realms of science, but i simply won't state them in yet another damn thread about sonix of electronix (cuz they will be taken WAY out of context).

I think it is important for the general audience to know, that we're not in any real disagreement. We may argue over semantics, or the possibility of extreme "outliers" in a statistical distribution ... but i don't think we're saying anything different of substance.

It's just that one of us is an engineer, and the other is a lawyer


----------



## MarkZ (Dec 5, 2005)

It's certainly _possible_ for an amplifier's performance to be well within spec (however we define it) driving resistive loads, and then tank under reactive loads -- either by shutting down or producing some sort of audible...um...artifact.

But I'll reiterate something I said earlier, to which you (lycan) echoed (or maybe you said it first...I don't remember  ): it's pretty easy and relatively cheap to design an amplifier that will behave "perfectly" under a varied assortment of (reasonable) loads... given that the design's minimum impedance isn't exceeded.

Why? Because amps with fairly high gain negative feedback usually have an extremely low output impedance, often dominated by the output zobel/protection circuitry (if it's got 'em). I wouldn't expect the FR or distortion performance to necessarily change appreciably (again, assuming "competent" design), and the noise characteristics shouldn't be affected. So I think you're being a bit conservative to entertain the notion that competently designed amps will change their characteristics to an audible level when put under (reasonable) reactive loads.

What might happen though (and this also goes for Manville's "squishy supply voltage" comment) is that the output capabilities of the amp decrease more for one amp than the other. But this isn't really a "sonic signature" issue. It's a "where does my amp clip?" issue, which is irrelevant to the conversation, IMO.

Anyway, I think one of the biggest problems in this thread is that nobody's defined "competent" yet.


----------



## lycan (Dec 20, 2009)

MarkZ said:


> It's certainly _possible_ for an amplifier's performance to be well within spec (however we define it) driving resistive loads, and then tank under reactive loads -- either by shutting down or producing some sort of audible...um...artifact.
> 
> But I'll reiterate something I said earlier, to which you (lycan) echoed (or maybe you said it first...I don't remember  ): it's pretty easy and relatively cheap to design an amplifier that will behave "perfectly" under a varied assortment of (reasonable) loads... given that the design's minimum impedance isn't exceeded.
> 
> ...


Again, no real disagreement ... but i don't think i'm being unreasonable in allowing for load variation (beyond resistive) to upset certain amplifiers.

Yes, it's very well known how to design otherwise (i think you said it first  ). But it *may* come down to cost. It's not a "small signal" issue; i absolutely agree that a negative feedback amplifier's output impedance will be positively _tiny_ compared to any reasonable load.

Instead, it's a question of large-signal heat, and stress. The lower impedance load will cause the output stage to be more thermally stressed ... when is a danger threshold crossed, for a given amplifier designed to a price point (and one that may measure fine at a higher impedance load)? And potentially _worse_ is a very reactive load, where simple impedance magnitude doesn't tell the whole story. A capacitive load is particularly nasty for any Class AB amp, because the output stage will be delivering it's HIGHEST current when the voltage across the output transistors are also at their HIGHEST ... unlike a resistive load ... meaning worst-case thermal stress of output devices under _reactive_, rather than resistive, load conditions.

Again, no disagreement on fundamental substance of the discussion. I just don't think it's very unreasonable to expect performance variation ... that may differ from one amp to another ... under reactive, versus tested-resistive, loads.


----------



## MarkZ (Dec 5, 2005)

cajunner said:


> I think the reactive/resistive issue falls under the "measures the same" umbrella, regardless.


No doubt. I think Manville's point was that it's another variable that needs to be accounted for, and that your measurements need to address it when trying to extrapolate sonics from a set of test parameters.

Which is sort of why I like DS-21's approach of forgetting what's under the hood, so to speak, and instead directly measuring outcomes.


----------



## lycan (Dec 20, 2009)

i think we all agree, that none of this load discussion refutes the validity, and comprehensive nature, of _electrical_ measurement.

Amps have to be specified _somehow_, with some kind of representative load. Surely small variations, at least, can't be expected to upset a "competently designed" amp 

And yes ... understanding the "stressful" nature of reactive, rather than purely resistive, loads is one of the factors (maybe the main one) that lead to the "power cube" representation of loads for amplifiers.


----------



## lycan (Dec 20, 2009)

lycan said:


> i think we all agree, that none of this load discussion refutes the validity, and comprehensive nature, of _electrical_ measurement.
> 
> Amps have to be specified _somehow_, with some kind of representative load. Surely small variations, at least, can't be expected to upset a "competently designed" amp
> 
> And yes ... understanding the "stressful" nature of reactive, rather than purely resistive, loads is one of the factors (maybe the main one) that lead to the "power cube" representation of loads for amplifiers.


EDIT : but i don't know that Rockford gets the credit for developing the "power cube" load representation ...


----------



## 14642 (May 19, 2008)

http://www.audiograph.se/

Here's the powercube guys. I do believe Rockford may have been the first company to use this thing to sell amps. I remember sitting through a training when I was a retail installer where our rep attempted to explain the measurement. Basically, the arguement was, "we have this book with all these measurements and that makes our amps sound better." Thank God for the Autosound 2000 guys who taught us all to make sure we didn't believe anything that any company ever told us about anything so we'd spend 10 bucks on their little newsletter from their company, which was the only one that ever told the truth so long as they weren't in the IASCA judging lanes.

Anyway, I digress. Carry on, mates.


----------



## 14642 (May 19, 2008)

Oh, and of course all amps and head units don't sound the same.


----------



## thehatedguy (May 4, 2007)

Easy fix or the gain knob variations...get rid of it with those coupling caps. 

Why does Milbert get all of the tube love? HSS is much nicer amp.

But what can I say, I love even order distortion profiles.

And I really respect JL amps for increasing power into reactive loads. Any amp can drive a resistor...but some are better than others when you throw in some back EMF etc to the mix. Most will decrease power output, but the JLs increase over resistive loads.


----------



## 14642 (May 19, 2008)

cajunner said:


> I am still at a loss for what happens in a Rockford amp that occurs a few minutes after warming up. I read somewhere that you shouldn't judge a Rockford amp on it's sonics until this period of time has passed, and I'll be darned if I don't hear a clearly audible difference when it happens.
> 
> Is it frequency response shaping? Is it a distortion reduction? Is it parts of the spectral response on a hold until some temperature differential is achieved? I thought it might have something to do with that, one of their trade-marked circuits is responsible, don't remember which one.


Who knows, but many amplifier manufacturers in the quest for ever sleeker and smaller heat sinks without fins use limiters that are activated when the heatsink temperature rises. Some of them have pretty nice transitions that make them difficult to hear and others are pretty abrupt.


----------



## kyheng (Jan 31, 2007)

^So, is it another reason why more and more brands opt for full range class-D?


----------



## 14642 (May 19, 2008)

kyheng said:


> ^So, is it another reason why more and more brands opt for full range class-D?


That's because many consumers don't want and don't have room for big-ass amps.


----------



## Niebur3 (Jul 11, 2008)

Andy Wehmeyer said:


> That's because many consumers don't want and don't have room for big-ass amps.


I personally think it is the notion (opposite of every other thing is our society that live by bigger is better) that when it comes to anything electronic, smaller is better and "cooler". Most people could give a **** how it sounds and long as it looks cool! Don't have the space...huh? Cars are bigger now than they have ever been in the past and it is also marketing that caused class "D" to be so popular due to manufacturers making inefficient as hell subs so they can tout how much "Power" they can handle, then you need a massive amp to power it...but it sells! Let me ask, would class D have ever caught on so well if the mass market subs were efficient enough to only need 100-200 watts?


----------



## MarkZ (Dec 5, 2005)

cajunner said:


> I think that approximating the voltage swings of a car in operation, as various appliances and loads are presented to the alternator/voltage regulator, is going to be difficult. An amp under these conditions, "squishy" voltages, may indeed have variable, potential moments to be audibly obvious, but this is dependent on the power supply. Then we get into the ol' 12V regulated, non-regulated thingy, 14.4V testing, CEA rears it's ugly head, and pretty soon we're in marketing margins, advertising has us by the balls.... and no longer in the "measures the same" ballpark, where the x=1 happens.
> 
> You can buy an amp to drive a particular load, but it doesn't mean that another amp that can drive several loads, is not better for the job.
> 
> ...


Yeah, it's really two completely unrelated issues. One is power output, and its dependence on certain variables. The other is "SQ", whatever that is. There's a third issue -- the one we've put to bed -- reliability.

I think people have a good handle on the reliability issue and the power output issue. It's that pesky other issue -- "SQ" -- that causes so many quarrels. My contention, and DS-21's, is that this is basically a non-issue in car audio land for the most part. Power output and reliability are very real considerations, on the other hand.


----------



## msmith (Nov 27, 2007)

Niebur3 said:


> Let me ask, would class D have ever caught on so well if the mass market subs were efficient enough to only need 100-200 watts?


In other words, if we didn't want subwoofers that played low and are able to get really loud in really small enclosures. If we all had 16 cu.ft. enclosures with one 15-inch pro driver, we wouldn't 'need' that much power. If we all weren't spoiled and expecting 130 dB plus from basic installations, we wouldn't 'need' that much power... :laugh:

What's funny is the home audio subwoofer market has followed the same path as the car audio subwoofer market... ever smaller subs with ever more powerful (Class D) amplifiers. Something about women not liking refrigerator-sized enclosures in the family room.


----------



## trigg007 (Feb 24, 2010)

msmith said:


> In other words, if we didn't want subwoofers that played low and are able to get really loud in really small enclosures. If we all had 16 cu.ft. enclosures with one 15-inch pro driver, we wouldn't 'need' that much power. If we all weren't spoiled and expecting 130 dB plus from basic installations, we wouldn't 'need' that much power... :laugh:
> 
> What's funny is the *home theater crowd * has followed the same path as the car audio subwoofer market... ever smaller subs with ever more powerful (Class D) amplifiers. Something about women not liking refrigerator-sized enclosures in the family room.


:laugh:


----------



## Niebur3 (Jul 11, 2008)

msmith said:


> In other words, if we didn't want subwoofers that played low and are able to get really loud in really small enclosures. If we all had 16 cu.ft. enclosures with one 15-inch pro driver, we wouldn't 'need' that much power. If we all weren't spoiled and expecting 130 dB plus from basic installations, we wouldn't 'need' that much power... :laugh:
> 
> What's funny is the home audio subwoofer market has followed the same path as the car audio subwoofer market... ever smaller subs with ever more powerful (Class D) amplifiers. Something about women not liking refrigerator-sized enclosures in the family room.


Removed to get back on topic


----------



## Oliver (Jun 25, 2007)

That worked exactly the same way Hoffman wrote his Iron Law.

A small box should be able to take more power due to acoustical spring loading , and subsequently produce more SPL.


----------



## sq_assasin (Nov 10, 2008)

msmith said:


> In other words, if we didn't want subwoofers that played low and are able to get really loud in really small enclosures. If we all had 16 cu.ft. enclosures with one 15-inch pro driver, we wouldn't 'need' that much power. If we all weren't spoiled and expecting 130 dB plus from basic installations, we wouldn't 'need' that much power... :laugh:
> 
> What's funny is the home audio subwoofer market has followed the same path as the car audio subwoofer market... ever smaller subs with ever more powerful (Class D) amplifiers. Something about women not liking refrigerator-sized enclosures in the family room.


Leave it to the guy that works for JL Audio to put down efficient woofers. I get it, all JL woofers are inefficient. I have heard that somewhere before.

The thing is, class d and inefficient woofers are good for SPL. You want SQ? An efficient woofer properly installed with mimimal power will provide more than you need.


----------



## sq_assasin (Nov 10, 2008)

Niebur3 said:


> I personally think it is the notion (opposite of every other thing is our society that live by bigger is better) that when it comes to anything electronic, smaller is better and "cooler". Most people could give a **** how it sounds and long as it looks cool! Don't have the space...huh? Cars are bigger now than they have ever been in the past and it is also marketing that caused class "D" to be so popular due to manufacturers making inefficient as hell subs so they can tout how much "Power" they can handle, then you need a massive amp to power it...but it sells! Let me ask, would class D have ever caught on so well if the mass market subs were efficient enough to only need 100-200 watts?


I agree. A lot of consumers don't pay attention to efficiency. All they care about is how much power the amp SAYS it will do and how much power the speakers STATE they can handle. Most have no clue that you can get just as loud with less power, and efficient woofers. And usually sound better doing it, IMO. 

Not to mention, less electrical load on your car to get just as loud as someone with double the power....if not triple.


----------



## mikey7182 (Jan 16, 2008)

sq_assasin said:


> Leave it to the guy that works for JL Audio to put down efficient woofers. I get it, all JL woofers are inefficient. I have heard that somewhere before.
> 
> The thing is, class d and inefficient woofers are good for SPL. You want SQ? An efficient woofer properly installed with mimimal power will provide more than you need.


You ought to do your homework before jumping to conclusions. Manville is quite the fan of efficient drivers, and was not putting them down. I have seen him hail the JBL 2123H on more than one occasion. Remember, a driver is only as efficient as the enclosure in which it is placed. The point he is making is that most people don't want to commit their entire trunk/hatch/bed to an enclosure for a single efficient driver. Check the specs on most efficient subwoofers, and you will find that they almost always require much larger enclosures than their less efficient counterparts. I ran a pair of JBL 2226G woofers in a blowthrough, and they were extremely efficient and had tons of output off very little power, but they needed 6+ cubes net a piece to achieve that. Take another 15" woofer that's much less efficient, but has a higher xmax, and throw it in a small sealed enclosure and feed it a few kilowatts, and achieve the same output. Worse on electrical? Definitely. Are there more efficient ways to achieve the same output? Of course. But it comes at the expense of automotive real estate, which is important to most people. Again, you have efficiency, power handling, and enclosure size. You can't have the best of all 3. Small sealed enclosures lower a driver's efficiency, but raise its power handling. Have less power on tap? Build a vented enclosure. Have a LOT less power on tap? Find a high efficiency woofer (most likely with a higher Fs than most subs) and build a MASSIVE vented enclosure or folded horn. And before your Masters instincts kick in and you lecture me on efficiency, check my sig and look at the gear I run.


----------



## msmith (Nov 27, 2007)

sq_assasin said:


> Leave it to the guy that works for JL Audio to put down efficient woofers. I get it, all JL woofers are inefficient. I have heard that somewhere before.
> 
> The thing is, class d and inefficient woofers are good for SPL. You want SQ? An efficient woofer properly installed with mimimal power will provide more than you need.


I didn't 'put down efficient woofers' in any way shape or form and I don't wish to further sidetrack this thread from its original topic. If you would like to learn something about woofer efficiency and how it relates to box volume and bandwidth, start a thread asking the question and I will be happy to explain it to you again.


----------



## sq_assasin (Nov 10, 2008)

msmith said:


> I didn't 'put down efficient woofers' in any way shape or form and I don't wish to further sidetrack this thread from its original topic. If you would like to learn something about woofer efficiency and how it relates to box volume and bandwidth, start a thread asking the question and I will be happy to explain it to you again.


Believe me, sir. I have nothing to learn when it comes to box building and woofer efficiency. I have been in the industry for 20+ years and I am quite confident I have built a hell of a lot more enclosures than you. There is no excuse for overly inefficient woofers. 

If I worked for the marketing department at JL, I would claim the same thing you do. It's your job. Some people don't get that and those are the people who simply believe your ******** and will never take the time to understand you gain nothing from JL's inefficient woofers.


----------



## Niebur3 (Jul 11, 2008)

sq_assasin said:


> Believe me, sir. I have nothing to learn when it comes to box building and woofer efficiency. I have been in the industry for 20+ years and I am quite confident I have built a hell of a lot more enclosures than you. There is no excuse for overly inefficient woofers.
> 
> If I worked for the marketing department at JL, I would claim the same thing you do. It's your job. Some people don't get that and those are the people who simply believe your ******** and will never take the time to understand you gain nothing from JL's inefficient woofers.


Sure you have!  Please get back on topic!!! BTW, Manville is not a marketing guy that doesn't know his product, he knows it VERY well and is very knowledgeable in car audio. I don't mind you questioning JL's philosophy, but please pay him the respect he has earned in this industry! You are fighting with one of the good guys here...not smart!


----------



## sq_assasin (Nov 10, 2008)

Niebur3 said:


> Sure you have!


There you go judging something you have no knowledge about. Pretty much all that happens here. And I get slack for stating opinions based on MY EXPERIENCE. Not what the forum wants to hear.

"Manville" uses efficient JBL woofers but pushes inefficient JL products on you guys. Now who is the fool?


----------



## sq_assasin (Nov 10, 2008)

cajunner said:


> How many times have you tried JL product in your 20+ years?
> 
> You don't know what you're talking about, with the efficiency argument. People have different goals for their sub systems, you might never listen to music that drops below 35 hz. Is that going to make people who listen to 20 hz and below statistically insignificant, or just outside of your purview?
> 
> ...


FYI - I have owned quite a few of their components over the years, and also quite a few woofers. As I stated, I don't state my opinions on items I haven't been able to play with or own.

I know a guy who recently replaced his 12" JLw3 with another more efficient woofer that wasn't even suppose to work optimally in the enclosure the w3 was in, and the increase in low end, SQ, and overall smoothness was immediately noticed. I have seen this many times over and over with their products. They are nothing special to warrant their cost.


----------



## Niebur3 (Jul 11, 2008)

sq_assasin said:


> FYI - I have owned quite a few of their components over the years, and also quite a few woofers. As I stated, I don't state my opinions on items I haven't been able to play with or own.
> 
> I know a guy who recently replaced his 12" JLw3 with another more efficient woofer that wasn't even suppose to work optimally in the enclosure the w3 was in, and the increase in low end, SQ, and overall smoothness was immediately noticed. I have seen this many times over and over with their products. They are nothing special to warrant their cost.


Read the damn title of this thread. Quit positing about this...if you want to, make your own damn thread!


----------



## mikey7182 (Jan 16, 2008)

Niebur3 said:


> Sure you have!  Please get back on topic!!! BTW, Manville is not a marketing guy that doesn't know his product, he knows it VERY well and is very knowledgeable in car audio. I don't mind you questioning JL's philosophy, but please pay him the respect he has earned in this industry! You are fighting with one of the good guys here...not smart!


Not just Manville, but Andy W., Lycan (somewhat indirectly), and many others. For a guy with so many years of experience and "an Masters degree" who has built more enclosures than God, you (sq_a) sure come off as a ****ing toolbag. I put you in your place last night with your ridiculous notion that increasing SNR never passes the threshold of human perception, which someone with such deep roots in the industry could recite in their sleep, and you're still banging heads with the big dogs here. The vast majority of us are here to learn, not to puff our chests. There are several people here who have earned the respect of the forum and thousands in the industry through years of hard work, innovation, and instruction to others. Three of those people you will find named at the beginning of this post, and you've managed to contradict all of them. Nobody gives two ****s about your false credentials, your ludicrous yammerings regarding electrical pathways, or your condescending spin on even the most trivial of opinions you deem worthy of permanence on the interwebz. Spend the next 6 months doing some serious reading on here so you can learn a few of the basics, or continue to open your mouth prematurely and embarrass yourself right off the forum. Oh, and it's Assassin, not assasin. It's surprising someone who makes acts like an ass with such consistency can't spell it twice in a row in their own username.


----------



## sq_assasin (Nov 10, 2008)

Niebur3 said:


> Read the damn title of this thread. Quit positing about this...if you want to, make your own damn thread!


I am sorry...am I the only one posting? Why are you directing this towards me?


----------



## sq_assasin (Nov 10, 2008)

mikey7182 said:


> Not just Manville, but Andy W., Lycan (somewhat indirectly), and many others. For a guy with so many years of experience and "an Masters degree" who has built more enclosures than God, you (sq_a) sure come off as a ****ing toolbag. I put you in your place last night with your ridiculous notion that increasing SNR never passes the threshold of human perception, which someone with such deep roots in the industry could recite in their sleep, and you're still banging heads with the big dogs here. The vast majority of us are here to learn, not to puff our chests. There are several people here who have earned the respect of the forum and thousands in the industry through years of hard work, innovation, and instruction to others. Three of those people you will find named at the beginning of this post, and you've managed to contradict all of them. Nobody gives two ****s about your false credentials, your ludicrous yammerings regarding electrical pathways, or your condescending spin on even the most trivial of opinions you deem worthy of permanence on the interwebz. Spend the next 6 months doing some serious reading on here so you can learn a few of the basics, or continue to open your mouth prematurely and embarrass yourself right off the forum. Oh, and it's Assassin, not assasin. It's surprising someone who makes acts like an ass with such consistency can't spell it twice in a row in their own username.


It's the people like you that make this all worthwhile. Attack my grammar and then make comments that all my credentials are lies.

I am not here to gain your respect, and if I did gain it, it would mean nothing to me. 

For your information, the word "an" is only used before a word starting with a vowel, or sometimes an abbreviation.

Now let's talk education seeing as you want to bring it up. All you people can't discredit my experience and advise so you attack grammar and education levels. I have obviously been quite successful seeing as I buy car audio equipment on a regular basis just to test and see if specs are true. Something most can't do. That is one reason my knowledge should be valued and not thrown around by a bunch of "high post count" "bandwagon jumping" "clique making" internet buddies.

I get to you...you don't get to me. The reason? I believe what I say, you don't.


----------



## sq_assasin (Nov 10, 2008)

cajunner said:


> so it's the cost that in the end, becomes the real reason you have a problem with JL product.
> 
> that's fine, if you can't pay for it, then crap on it, eh?
> 
> ...


Can't afford it? Way to switch my words around. That is one thing you guys are good at. Pulling things out of the air. Now you want to talk money? See what I mean.

It is figured out.


----------



## MarkZ (Dec 5, 2005)

sq_assasin said:


> There you go judging something you have no knowledge about. Pretty much all that happens here. And I get slack for stating opinions based on MY EXPERIENCE. Not what the forum wants to hear.
> 
> "Manville" uses efficient JBL woofers but pushes inefficient JL products on you guys. Now who is the fool?


Manville explained to you in post #193 why there's a market for less efficient subwoofers. You don't read. Instead you judge him based on what you perceive is his intent. Here is yet ANOTHER case where you ignore the content of someone's post and instead attack their credibility, experience, or affiliation. All any of us are asking from you is that you start addressing the points that other people make instead of just ****ting all over their posts indiscriminately. You don't like his opinion? FINE. Explain why he's wrong. Don't start citing your unverifiable credentials and levying ad hominem attacks at everybody else.


----------



## sq_assasin (Nov 10, 2008)

MarkZ said:


> Manville explained to you in post #193 why there's a market for less efficient subwoofers. You don't read. Instead you judge him based on what you perceive is his intent. Here is yet ANOTHER case where you ignore the content of someone's post and instead attack their credibility, experience, or affiliation. All any of us are asking from you is that you start addressing the points that other people make instead of just ****ting all over their posts indiscriminately. You don't like his opinion? FINE. Explain why he's wrong. Don't start citing your unverifiable credentials and levying ad hominem attacks at everybody else.


I think this was meant for your buddies....not me. I accept your apologies.


----------



## mikey7182 (Jan 16, 2008)

sq_assasin said:


> It's the people like you that make this all worthwhile. Attack my grammar and then make comments that all my credentials are lies.
> 
> I am not here to gain your respect, and if I did gain it, it would mean nothing to me.
> 
> ...


For my information? In which alphabet is the letter "M" a vowel? You're not actually so dense as to completely miss the fact that you are the one who said you had "AN Masters Degree (sic)" then ninja-edited it by the time I had quoted you, are you? Do I bust your balls over your grammar? You bet your ass I do. You love to keep honing in on that single point though, while minimizing my criticism of your ridiculous claims. I didn't type that entire paragraph out and dedicate it solely to your horrible grammar, punctuation, and spelling. But if you'd like to cherry pick and brush the rest of it under the rug, that's your decision. 

I'll say it again- *your take on the whole SNR thing is borderline retarded. Seriously.* So for all us people who can't discredit your experience and advise (sic- it's ADVICE, douche), I just did. I even bolded it for convenient reference. Your level of "success" (I'm assuming you're attempting to draw a parallel between your alleged Master's degree and the size of your bank account) is irrelevant. Nobody cares how much gear you buy solely for testing purposes, especially since you seem to have less than the slightest clue how to interpret the measurements anyway. I bust your balls on grammar because you continue to throw your high level of education in our faces. You're picking that fight, not me. The irony of a grammatical error in the same sentence you're proclaiming you've earned a graduate degree is too much to pass up.

So do you get to me? I guess it depends on how you'd define "get." I can promise you though, that any level of annoyance I feel toward you has absolutely nothing to do with self-affirmation, and everything to do with your irrational, illogical, changes-by-the-minute, fence-sitting stance on just about everything you type. And to call someone who doesn't get to you a simpleton, followed by some obscure analogy about water and hair was amusing, so thanks for that.  Carry on.


----------



## MarkZ (Dec 5, 2005)

sq_assasin said:


> I think this was meant for your buddies....not me. I accept your apologies.


Seriously?

Ok, new addition to the ignore list.


----------



## msmith (Nov 27, 2007)

Stop feeding the troll, guys. Back on topic, please.


----------



## sq_assasin (Nov 10, 2008)

mikey7182 said:


> In which alphabet is the letter "M" a vowel? You're not actually so dense as to completely miss the fact that you are the one who said you had "AN Masters Degree (sic)" then ninja-edited it by the time I had quoted you, are you?


Prove it. I can lie about you too seeing as that's what you are trying to pull.



mikey7182 said:


> So for all us people who can't discredit your experience and advise (sic- it's ADVICE, douche), I just did. I even bolded it for convenient reference.


Sure looks like you capitalized it to me, not "bolded it". That could be my minimal education speaking and I could be wrong (according to you).

Thanks for the name calling. I will be obliged to report you as well, seeing as I am not breaking the rules and you are. Isn't America great!!!


----------



## sq_assasin (Nov 10, 2008)

msmith said:


> Stop feeding the troll, guys. Back on topic, please.


Troll? Ha.

He's right. Let us go back to listening to "The JL Audio Guy" tell us why JL Audio is so great and how their published specs somehow defy physics. 

What else can you expect from a marketing rep?


----------



## mikey7182 (Jan 16, 2008)

sq_assasin said:


> Prove it. I can lie about you too seeing as that's what you are trying to pull.


You've cowered down behind "prove it" eh? You and I both know I can't. It's just something we'll both know about you. That's satisfactory enough for me.



sq_assasin said:


> Sure looks like you capitalized it to me, not "bolded it". That could be my minimal education speaking and I could be wrong (according to you).
> 
> Thanks for the name calling. I will be obliged to report you as well, seeing as I am not breaking the rules and you are. Isn't America great!!!


Oh, Christ. We've got an incompetent lawyer on our hands. I bolded the sentence previous- the one to which I was referring. Sometimes, we can refer to things after we've completed the sentence/paragraph/page on/in which said information was located. Try and keep up, will you? America isn't that great, and neither is its native language. 

Report me if you must. Or if you'd like, I'll just call Ant myself and ask him to ban me. I need to get Andrew's number so I can order some more product at cost anyway. With that, I bid you adieu.


----------



## lycan (Dec 20, 2009)

msmith said:


> Stop feeding the troll, guys. Back on topic, please.


wisdom for the ages ...


----------



## thehatedguy (May 4, 2007)

IMO it would be a bland world where every amp sounded the same. I like single ended triodes and would be tickled pink if I could have all of my amps sound like my HSS Fidelity tube amp...well, maybe not for bass. I wish I was smart enough to make brand x amp sound like my HSS, but I'm not on that level. Yeah I like even order distortion...I said it.

But I do wholeheartedly agree that if I could measure what makes my HSS sound the way it does, that I could make something else sound the same...I don't know how. And it would be foolish to argue that there is some magic out there that says if two electronic devices that measured in all ways pretty similar then they would sound anything other than similar. It took me a long time to wrap my head around that concept, but it is truth and not a suggestion.


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> IMO it would be a bland world where every amp sounded the same. I like single ended triodes and would be tickled pink if I could have all of my amps sound like my HSS Fidelity tube amp...well, maybe not for bass. I wish I was smart enough to make brand x amp sound like my HSS, but I'm not on that level. Yeah I like even order distortion...I said it.
> 
> But I do wholeheartedly agree that if I could measure what makes my HSS sound the way it does, that I could make something else sound the same...I don't know how. And it would be foolish to argue that there is some magic out there that says if two electronic devices that measured in all ways pretty similar then they would sound anything other than similar. It took me a long time to wrap my head around that concept, but it is truth and not a suggestion.


Following up on the Carver article, i might start my own poll  I know, with complete certainty, that most people will get the answer to this question _wrong_  Well, audiophiles will fail ... maybe not anyone disciplined in science and logic.

I've got two _different_ amplifiers, but three _virtually identical_ loudspeakers. One speaker connected to one amplifier, second speaker connected to other amplifier. The third speaker is connected _between_ the positive outputs of the two amps, so it's "listening" to the _difference_ between the _electrical ouptuts_ of the two amps. Somehow, through measures extra-ordinary or quite modest, the third speaker is silent, with any music you care to play ... even though the two amps are branded differently, and cost differently.

Is it possible for the first two speakers to sound different?

Stereophile gurus failed this test miserably.


----------



## msmith (Nov 27, 2007)

The term "virtually identical" used to describe the speakers leads me to believe they are not identical in performance.

Measuring across the amplifiers' positives and having zero output leads me to think the amplifiers are outputting signals sufficiently similar to not generate an audible result.

The two speakers individually connected to the amplifier can certainly sound different, but any audible difference would be attributable to differences between the speakers, not the amplifiers.


----------



## lycan (Dec 20, 2009)

msmith said:


> The term "virtually identical" used to describe the speakers leads me to believe they are not identical in performance.
> 
> Measuring across the amplifiers' positives and having zero output leads me to think the amplifiers are outputting signals sufficiently similar to not generate an audible result.
> 
> The two speakers individually connected to the amplifier can certainly sound different, but any audible difference would be attributable to differences between the speakers, not the amplifiers.


listen smarty pants ... you know i avoided the phrase "identical loudspeakers" because those poll-takers without any critical reasoning skills would immediately "shut down" on the physical impossibility of identical ... anythings 

If i need to qualify my new poll with "same brand & model loudspeakers, audibly identical in all respects", i will


----------



## DS-21 (Apr 16, 2005)

Wouldn't wiring a speaker in the manner of the third (both positive leads) just be likely to blow both amps?

And two entirely identical speakers can still sound quite different. Aim one straight at you, and tip the other over such that its drive-units are on the floor?


----------



## lycan (Dec 20, 2009)

DS-21 said:


> Wouldn't wiring a speaker in the manner of the third (both positive leads) just be likely to blow both amps?
> 
> And two entirely identical speakers can still sound quite different. Aim one straight at you, and tip the other over such that its drive-units are on the floor?


you guys are impossible.

Like MY new poll has all this ambiguity, but "competently designed" doesn't? sheeesh

but no ... wiring the third speaker as described won't blow the amps. In fact, the amps won't even know it's present, if they are not delivering any current to it  Load #3 is "bridged", with identical drive from both sides ... the amps won't even "see" the load.

Plus i thought we weren't even _worrying_ about load impedance for amps?  

Come on ... take my new poll  You guys know there's only one right answer ...

else you're about to lead the general audience down a path you don't want to go ...


----------



## msmith (Nov 27, 2007)

Lycan... 

It's not officially an audio geek puzzle unless you use the phrase: "all other things being equal".


----------



## lycan (Dec 20, 2009)

msmith said:


> Lycan...
> 
> It's not officially an audio geek puzzle unless you use the phrase: "all other things being equal".


i hear ya  but in my humble (yet correct) opinion, it's more than a simple puzzle.

i think my new poll establishes an interesting "boundary condition" that, i strongly suspect, many fail to appreciate


----------



## thehatedguy (May 4, 2007)

No fair, you don't have multiple guess answers to choose from.

But if it is following something like the Carver test, then there wouldn't be any audible differences between the speakers since the 3rd set isn't playing anything...so the other set would sound virtually the same.


----------



## lycan (Dec 20, 2009)

if the voltages to two identical speakers are identical, is there any way for them to sound different (to identical listeners in identical orientations)?

Trust me ... the answer may sound trivial when the question is phrased like this, but it's far from obvious to many.


----------



## thehatedguy (May 4, 2007)

Could you not have some phasing issue at the speaker that could cause an issue? Or what about physical size? A 3 way with an 18 and some horns would convert said energy more effectively than a 2 way bookshelf with a 4 and tweeter.


----------



## Thoraudio (Aug 9, 2005)

methinks we have come upon the reason the amp challenge has rules......


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> Could you not have some phasing issue at the speaker that could cause an issue? Or what about physical size? A 3 way with an 18 and some horns would convert said energy more effectively than a 2 way bookshelf with a 4 and tweeter.





lycan said:


> if the voltages to two *identical* speakers are identical, is there any way for them to sound different (to identical listeners in identical orientations)?.


If i have two IDENTICAL loudspeakers, the same voltage must produce the same output. There's no other way for amplifiers to "commune" with speakers.

OR ... if the voltage to the SAME loudspeaker is the same from one hour to the next, the speaker will react the same. It has no choice.

Certainly, the same voltage to a subwoofer would produce very different results when applied to a tweeter. Does that invalidate the hypothesis? Those two amps sure "sound" different !!!! 

Reminds of another fun question :

"Why must we compare amplifiers on identical speakers? In the "real world", amplifiers drive different speakers all the time !!!"

Isn't it much more realistic, in the real world, to compare amplifiers while they are driving different speakers, in very different vehicles?


----------



## sq_assasin (Nov 10, 2008)

lycan said:


> If i have two IDENTICAL loudspeakers, the same voltage must produce the same output. There's no other way for amplifiers to "commune" with speakers.
> 
> OR ... if the voltage to the SAME loudspeaker is the same from one hour to the next, the speaker will react the same. It has no choice.
> 
> ...




Not necessarily. My bench has had the same setup for years. Same speakers, headunit...etc. The only item that gets swapped for amp testing is the amps. 

I am a believer that amps and headunits DO sound different. Once again, experience tells me this. It's not hard to determine.

I don't believe an increase in voltage (power) changes the sound of the amp, it only increases dynamics in your speaker. The sonic properties aren't dramatically changed by an increase in power output.


----------



## SoundChaser (Apr 3, 2009)

lycan said:


> if the voltages to two identical speakers are identical, is there any way for them to sound different (to identical listeners in identical orientations)?
> 
> Trust me ... the answer may sound trivial when the question is phrased like this, but it's far from obvious to many.


Yes, 1 speaker is brand new and the other one is sufficiantly broken in.


----------



## lycan (Dec 20, 2009)

SoundChaser said:


> Yes, 1 speaker is brand new and the other one is sufficiantly broken in.


... and you would still call those two speakers _identical_ ????

i wouldn't.


----------



## kyheng (Jan 31, 2007)

Interesting...... I like forums..... 
But ask ourself something :
1. does all amps really sound the same?
2. does a ceramic resistor sounds the same as MOX resistor?
3. does an electrolytic capacitors sounds the same as foil capacitors?
4. is our ears properly calibrated?
5. can we listen the same loudness from both of our ears?


----------



## thehatedguy (May 4, 2007)

Does one set of speakers have cable elevators holding the speaker wire off of the floor?


----------



## lycan (Dec 20, 2009)

cajunner said:


> interesting.
> 
> I think you threw a clue with "stereophile", meaning that this amplifier duo as such, is really a stereo amplifier...
> 
> ...


no.

Two amps each receive the same signal. No inversion required. Each amplifier is a monoblock amplifier. Or we only ever pay attention to one channel of a stereo amp. There's no bridging or inversion switches within 12 miles of our test.

Each mono amp drives one speaker, plus a third speaker connected between the positive outputs of the two amps. The idea is simply this : the third speaker "listens" to the electrical _difference_ between the two amplifiers. If the third speaker is silent, this means the electrical signal to each of the first two speakers is IDENTICAL.

Can two identical speakers sound different, if the voltages driving them are identical? That's the WHOLE question ... NOTHING more.

Yes ... we are assuming that the two identical speakers are identically positioned. It's NOT a "trick question", like ... AHA !!!! one of the speakers is facing forward, and the other is facing backward. Or ... AHA !!!! One of the speakers is buried in a muddy concrete mixture, and the other isn't ... so of course, they sound different.

*The WHOLE question is simply this : two identical speakers, driven with identical voltages from *different* amplifiers. Do the speakers sound the same? By what mechanism could they possibly sound different? WHAT DOES A SPEAKER "KNOW" ABOUT THE AMPLIFIER DRIVING IT, THAT CAN NOT BE FOUND IN THE VOLTAGE AT ITS TERMINALS ????*

Seriously ... if this is mind-bendingly confusing, abstract beyond all reason, impossible to answer ... then i give up. really. any meaningful comparison of any electronic equipment will be completely impossible, until this question is understood.

EDIT : if you don't understand the question, or find it impossible to answer ... don't feel bad. The audio reviewers at Stereophile don't understand it either. They still think that voltage is only one thing in the communion between an amplifier and loudspeaker. They still think that the speaker somehow magically "knows" the brand and cost of the amplifier driving it. They still think that if two identical loudspeakers are driven with identical voltages, we still can NOT conclude that they have no choice but to sound identical ... unless we know brand names & costs.


----------



## mikey7182 (Jan 16, 2008)

lycan said:


> no.
> 
> Two amps each receive the same signal. No inversion required.
> 
> ...


Out of all the explanations you've given on various subjects, I just might appreciate this one the most. Thank you.


----------



## MarkZ (Dec 5, 2005)

Maybe one of lycan's implied targets, John Atkinson, argues:

Stereophile: Absolute Issues



> Unfortunately, it can happen that scientific objectivity nevertheless leads to erroneous conclusions. First, although measurements will always have *some connection* with sound quality, the connection can often be tenuous; when those measurements are interpreted, the subjective nature of interpretation can render an "objective" test rather less so. Second, you will never be sure that, by minimizing the variables under test and by making the test procedures practicable, you have not changed the situation so much that the results will not be applicable to real life. It is on this small rock, for example, that "scientific" listening tests of the kind demanded by Stereo Review readers, the followers of Julian Hirsch and David Clark, often founder. To make the test performable, it can become too far removed from the real experience.


[bolded for effect]

Sounds like some people in here... 

[BTW, if you guys want to "cheat" and figure out the answer to lycan's question, see footnote 2 in that article which links to two experiments that have done basically what lycan describes...]


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> no.
> 
> Two amps each receive the same signal. No inversion required. Each amplifier is a monoblock amplifier. Or we only ever pay attention to one channel of a stereo amp. There's no bridging or inversion switches within 12 miles of our test.
> 
> ...


Obviously voltage isn't the only thing you mentioned that make an audible difference. Noise is something that is not apparent if you are just measuring voltage and neither is the frequency response. So, yes, there could still be an audible difference (I hope...lol).

As far as all amp measuring the same will sound the same.....I can agree with all of this is as long as the amp is "happy". But, please correct me if I am wrong, once the amp is driven hard, won't headroom differences or differences in the way the amp handles clipping cause there to Possible audible differences that are very apparent?


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> Obviously voltage isn't the only thing you mentioned that make an audible difference. Noise is something that is not apparent if you are just measuring voltage and neither is the frequency response. So, yes, there could still be an audible difference (I hope...lol).


By "voltage", he meant...well...voltage. You can measure voltage with much more sophisticated tools than a digital voltmeter, if that's what you're thinking of. 



> As far as all amp measuring the same will sound the same.....I can agree with all of this is as long as the amp is "happy". But, please correct me if I am wrong, once the amp is driven hard, won't headroom differences or differences in the way the amp handles clipping cause there to Possible audible differences that are very apparent?


Maybe. But then you'd hear that difference in the third speaker.


----------



## Thoraudio (Aug 9, 2005)

MarkZ said:


> Maybe one of lycan's implied targets, John Atkinson, argues:
> 
> Stereophile: Absolute Issues
> 
> ...



so, its there, but it's inherently untestable?


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> Obviously voltage isn't the only thing you mentioned that make an audible difference. Noise is something that is not apparent if you are just measuring voltage and neither is the frequency response. So, yes, there could still be an audible difference (I hope...lol).


oh dear 

Noise is absolutely apparent if you are measuring voltage. Not necessarily with the hand-held DMM  "Noise" is a (usually small) random fluctuation (with typically well-defined statistical & spectral behavior) in ... you guessed it ... _voltage_.

Frequency response ABSOLUTELY is apparent when you measure voltage. Pick a 1kHz test tone ... measure the AC voltage with your hand-held DMM. Now repeat the test with a 50Hz test tone, and a 5kHz test tone. Don't look now ... but you've just been measuring the _frequency response_. 

Seriously guys ... the speaker ONLY knows about the voltage driving it. I'm kinda surprised that someone hasn't suggested _current_  but then there's that pesky Ohm's Law thing again ....

*told you guys that my poll would be a real eye-opener* 


> As far as all amp measuring the same will sound the same.....I can agree with all of this is as long as the amp is "happy". But, please correct me if I am wrong, once the amp is driven hard, won't headroom differences or differences in the way the amp handles clipping cause there to Possible audible differences that are very apparent?


Yes ... very apparent in the VOLTAGE.


----------



## lycan (Dec 20, 2009)

MarkZ said:


> Maybe one of lycan's implied targets, John Atkinson, argues:
> 
> Stereophile: Absolute Issues
> 
> ...


Seriously, that Stereophile dude is blithering idiot ... can't believe he actually attempts to make a living at _comparing_ audio devices. People will fall for anything ...

nobody jumped on my "real world" complaint:

"_Why must we compare amplifiers on the *same set* of speakers? I mean, that might be fine in your so-called "laboratory", but here in the REAL WORLD amplifiers drive different speakers all the time! Plus, the amplifiers do it in DIFFERENT cars! So all this "controlling variables" makes no sense, in the REAL world. I know amps sound different, because i listened to the Bangkracker in my 98 civic with Truesound speakers, and it sounded WAY different than the Nutbanger in my buddies 92 camaro with the ****spasms. A real-wolrd test ... and the amplifiers sounded WAY different!!! _"

If the answer, or resolution, to this apparent conflict is NOT immediately apparent, you have no business allowing thoughts of audio device comparisons to enter your mind.


----------



## gijoe (Mar 25, 2008)

I have been trying to follow along, and one thing I keep seeing is people throwing out "headroom" and clipping. I'm trying to understand how this would matter. If you are clipping the signal wouldn't you be changing the frequency response and therefor causing an audible change? The idea of the power supply and headroom seems like a non issue if both amps are matched to run below the weaker amps clipping point. These things come into play when the you clip on the peaks, but this changes the FR and therefor the voltage no longer measures the same.

Am I getting this part?


----------



## 89grand (Nov 23, 2006)

cajunner said:


> well, in MY car, my Sony class D amplifier sounds great, and I heard a Soundstream class D amplifier in my buddy's truck, and it sounded crappy!
> 
> :surprised:


I have a cheap Sony class D in my Jeep and it sounds fine too. Your buddy may have a number of issues going on that are not even related to the amp, in fact that's most likely the case.


----------



## msmith (Nov 27, 2007)

lycan said:


> Seriously, that Stereophile dude is blithering idiot ... can't believe he actually attempts to make a living at _comparing_ audio devices. People will fall for anything ...
> 
> nobody jumped on my "real world" complaint:
> 
> ...


*The audiophile argument goes something like this:
*"The amplifier, speakers and cables all form an organism that exhibits behaviors not explainable with simple electrical or acoustic measurement. Only the golden-eared audiophile can hear it, plain as day, by listening to carefully selected recordings of music nobody wants to hear, done by guys who nobody wants to share air space with. It's easy to destroy the performance of a perfectly good amplifier by using the 'wrong' type of speakers for it, or vice-versa! And a set of cables can make a huge difference, in some cases fixing the amplifier-speaker mismatch. It's all true... all you have to do is listen."

You can't use reason to argue against faith. The faith-based argument is attractive because it appeals to emotion and excitement. The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


----------



## benny z (Mar 17, 2008)

msmith said:


> You can't use reason to argue against faith. The faith-based argument is attractive because it appeals to emotion and excitement. The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


quoted for truth.



msmith said:


> You can't use reason to argue against faith. The faith-based argument is attractive because it appeals to emotion and excitement. The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


...and again.


----------



## DS-21 (Apr 16, 2005)

msmith said:


> The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


I would say that the passion is misplaced then. For a consumer to be passionate about commodity signal-enlargers is frankly kind of weird. Certainly, it has nothing to do with the ostensible purpose of audio, which is to reproduce _music._ 

The whole point of *all* the gear, IMO, is to get out of the damn way of the music.

Nothing wrong with being passionate about making a better amp, mind. I assume your engineers, and those at PowerPhysics, are such people, and we're all better of for it. But those are also people who can see beauty and elegance and even gratification in "simple numbers and graphs."


----------



## msmith (Nov 27, 2007)

DS-21 said:


> I would say that the passion is misplaced then. For a consumer to be passionate about commodity signal-enlargers is frankly kind of weird. Certainly, it has nothing to do with the ostensible purpose of audio, which is to reproduce _music._
> 
> The whole point of *all* the gear, IMO, is to get out of the damn way of the music.
> 
> Nothing wrong with being passionate about making a better amp, mind. I assume your engineers, and those at PowerPhysics, are such people, and we're all better of for it. But those are also people who can see beauty and elegance and even gratification in "simple numbers and graphs."


No argument from me on any of your points. I'm just pointing out the reasons why many people prefer the other side of the coin.


----------



## lycan (Dec 20, 2009)

gijoe said:


> I have been trying to follow along, and one thing I keep seeing is people throwing out "headroom" and clipping. I'm trying to understand how this would matter. If you are clipping the signal wouldn't you be changing the frequency response and therefor causing an audible change? The idea of the power supply and headroom seems like a non issue if both amps are matched to run below the weaker amps clipping point. These things come into play when the you clip on the peaks, but this changes the FR and therefor the voltage no longer measures the same.
> 
> Am I getting this part?


Clipping changes the harmonic DISTORTION (remember that spec?) of the signal. It can be heard, it can be measured, and it absolutely shows up in the measured voltage. If one amp is clipping and another isn't, that means that the DISTORTION performance of the amplifiers will no longer be the same. This may very well be audible, and it will certainly be measurable.

It is NOT the case that the signal starts clipping, but the voltage driving the loudspeaker "doesn't know about it".

And, in my new poll, if identical speaker #3 remains SILENT ... then it doesn't matter if amplifiers #1 and #2 are clipping. Amps #1 and #2 must be clipping identically, for speaker #3 to remain silent


----------



## lycan (Dec 20, 2009)

DS-21 said:


> I would say that the passion is misplaced then. For a consumer to be passionate about commodity signal-enlargers is frankly kind of weird. Certainly, it has nothing to do with the ostensible purpose of audio, which is to *reproduce* _music._
> 
> The whole point of *all* the gear, IMO, is to get out of the damn way of the music.


These damn amplifiers & headunits aren't _creating_ the music! I concur, completely. The passion is in THE MUSIC  not the reproduction chain 

I've said .. don't confuse the Mona Lisa with the glass in front of her! Actually, i'm not sure if there really _is_ glass in front, because by the most remarkable coincidences the 3 times i've been to the Louvre the damn thing has been closed  I was tempted to break-in, kinda like i did at the Paris Opera House, but those damn French police simply have no sense of adventure.


----------



## thehatedguy (May 4, 2007)

Was post 231 not correct?


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> Was post 231 not correct?


no.

"was post 231 correct?"
yes.


----------



## mikey7182 (Jan 16, 2008)

lycan said:


> These damn amplifiers & headunits aren't _creating_ the music! I concur, completely. The passion is in THE MUSIC  not the reproduction chain
> 
> I've said .. don't confuse the Mona Lisa with the glass in front of her! Actually, i'm not sure if there really _is_ glass in front, because by the most remarkable coincidences the 3 times i've been to the Louvre the damn thing has been closed  I was tempted to break-in, kinda like i did at the Paris Opera House, but those damn French police simply have no sense of adventure.


If you can act better than Tom Hanks, who has been jockeying for years against Keanu Reeves for the title "Personality most closely resembling that of a 2x4," you might have a shot at a role in the next Dan Brown movie.


----------



## lycan (Dec 20, 2009)

mikey7182 said:


> If you can act better than Tom Hanks, who has been jockeying for years against Keanu Reeves for the title "Personality most closely resembling that of a 2x4," you might have a shot at a role in the next Dan Brown movie.


don't forget Harrison Ford, in the contest for highest salary/talent quotient.

Best high-profile actor working today? DiCaprio, hands-down.


----------



## mikey7182 (Jan 16, 2008)

lycan said:


> don't forget Harrison Ford, in the contest for highest salary/talent quotient.
> 
> Best high-profile actor working today? DiCaprio, hands-down.


Harrison should have been hit by those poison darts. Or been crushed by that massive boulder. Or crashed and died on Air Force One. Or been blown up in that Columbian drug war. Or gotten HepB from that Skeletor-look-alike he's been shagging. 

Shutter Island, Inception, Blood Diamond... all epic. He has come quite a ways since his Titanic days. 

Back to voltage.


----------



## envisionelec (Dec 14, 2005)

msmith said:


> *The audiophile argument goes something like this:
> *"The amplifier, speakers and cables all form an organism that exhibits behaviors not explainable with simple electrical or acoustic measurement. Only the golden-eared audiophile can hear it, plain as day, by listening to carefully selected recordings of music nobody wants to hear, done by guys who nobody wants to share air space with. It's easy to destroy the performance of a perfectly good amplifier by using the 'wrong' type of speakers for it, or vice-versa! And a set of cables can make a huge difference, in some cases fixing the amplifier-speaker mismatch. It's all true... all you have to do is listen."
> 
> You can't use reason to argue against faith. The faith-based argument is attractive because it appeals to emotion and excitement. The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


What a boring answer! 

What we need is some _excitement_... Create excitement. Create illusion. Create differences. 

Who coined the term "old school amp" on eBay to sell sh*t amps for a mint? It's not logical, it's _exciting!_ I recently responded to a thread about some Fultron amp porn. *JAKT*. "*J*ust *A*nother *K*orean *T*urnkey." 

It'll be the next phrase, "Aww man, this amp isn't old-school; it's *JAKT*!"


----------



## MarkZ (Dec 5, 2005)

mikey7182 said:


> Harrison should have been hit by those poison darts. Or been crushed by that massive boulder. Or crashed and died on Air Force One. Or been blown up in that Columbian drug war. Or gotten HepB from that Skeletor-look-alike he's been shagging.
> 
> Shutter Island, Inception, Blood Diamond... all epic. He has come quite a ways since his Titanic days.
> 
> Back to voltage.


Before titanic there was gilbert grape, where he also did a good job.

I think Titanic was just one of those sappy disneyfied formula-driven movies that the director intentionally makes the actors suck in so that the simple-minded audience gets to feel emo for the day.


----------



## thehatedguy (May 4, 2007)

What if one speaker had cable elevators and quantum purifiers?

 



lycan said:


> no.
> 
> "was post 231 correct?"
> yes.


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> What if one speaker had cable elevators and quantum purifiers?


how do they impact the measurable voltage at the terminals of the identical speakers?


----------



## msmith (Nov 27, 2007)

lycan said:


> These damn amplifiers & headunits aren't _creating_ the music! I concur, completely. The passion is in THE MUSIC  not the reproduction chain


The passion, for many, is in the chase for sonic perfection... whatever that might be in each of our minds filled with unique sets of preconceived notions about how things should sound. :laugh:


----------



## TREETOP (Feb 11, 2009)

msmith said:


> *The audiophile argument goes something like this:
> *"The amplifier, speakers and cables all form an organism that exhibits behaviors not explainable with simple electrical or acoustic measurement. Only the golden-eared audiophile can hear it, plain as day, by listening to carefully selected recordings of music nobody wants to hear, done by guys who nobody wants to share air space with. It's easy to destroy the performance of a perfectly good amplifier by using the 'wrong' type of speakers for it, or vice-versa! And a set of cables can make a huge difference, in some cases fixing the amplifier-speaker mismatch. It's all true... all you have to do is listen."
> 
> You can't use reason to argue against faith. The faith-based argument is attractive because it appeals to emotion and excitement. The reason-based argument is boring, clinical and analytical and reduces that which we are passionate about to simple numbers and graphs. It's not gratifying.


This reminds me of church. :blush:


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> Noise is absolutely apparent if you are measuring voltage. Not necessarily with the hand-held DMM  "Noise" is a (usually small) random fluctuation (with typically well-defined statistical & spectral behavior) in ... you guessed it ... _voltage_.
> 
> Frequency response ABSOLUTELY is apparent when you measure voltage. Pick a 1kHz test tone ... measure the AC voltage with your hand-held DMM. Now repeat the test with a 50Hz test tone, and a 5kHz test tone. Don't look now ... but you've just been measuring the _frequency response_.
> 
> Yes ... very apparent in the VOLTAGE.


Again, not trying to argue, just trying to learn. So all these are apparent in the measured voltage. So, again not to :dead_horse: ...well, you get the idea, but I still have a few questions about this. So, an amp that measures the same MUST sound the same, but no 2 amps sound the same due to variances that cause the voltage to be different...correct? With that said, if I am looking at amps from 2 or 3 different companies, do I trust the manufacturer specs that are either unreliable or derived under different conditions/testing methods, or just assume (I hate the meaning of that word) that any difference would be below the threshold of human hearing and that they would sound/perform the same, since I cannot afford to buy them all and test myself? I mean, if I eq a 6dB increase at 1K, do I "assume" every amp I am considering will handle this appropriately? If everything else is the same, do I look for the amp with the most power or largest headroom?


----------



## MarkZ (Dec 5, 2005)

Niebur3 said:


> Again, not trying to argue, just trying to learn. So all these are apparent in the measured voltage. So, again not to :dead_horse: ...well, you get the idea, but I still have a few questions about this. So, an amp that measures the same MUST sound the same, but no 2 amps sound the same due to variances that cause the voltage to be different...correct?


Only if the random component (the noise) is audible.

This goes for everything else too. Two amps (even identical ones) won't have identical outputs down to the nearest electron. There's *always* some variation, even if it's due to Johnson noise. It's a statistical impossibility for the two outputs to always be completely and utterly identical. But that's not the issue. The question is whether or not differences between amplifiers are _audible_.



> With that said, if I am looking at amps from 2 or 3 different companies, do I trust the manufacturer specs that are either unreliable or derived under different conditions/testing methods, or just assume (I hate the meaning of that word) that any difference would be below the threshold of human hearing and that they would sound/perform the same, since I cannot afford to buy them all and test myself? I mean, if I eq a 6dB increase at 1K, do I "assume" every amp I am considering will handle this appropriately? If everything else is the same, do I look for the amp with the most power or largest headroom?


Manufacturers almost invariably do an extremely crappy job at describing amplifier performance. If you buy a stupid 99 cent op amp, you'll get performance measurements out the wazoo across dozens of parameters. An audio amplifier that costs hundreds of dollars doesn't have any of this. So, no, I wouldn't trust manufacturer specs all that much.

I know this sort of makes this whole discussion about measurements difficult to apply when trying to choose amplifiers. The point of the discussion is more about conceptual understanding of how they can potentially differ and how to establish, objectively, how two given amplifiers would.


----------



## thehatedguy (May 4, 2007)

Cause the cable elevators lift the cables off of the floor so you don't have as much dielectric smearing going on...and less electron pooling. And I don't even have to tell you how that could effect voltage. I mean these poor electrons get trapped in these quantum pools and slow down, or worse, get stuck. How awful is that?

<goes and rearranges his shakti stones>


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> Again, not trying to argue, just trying to learn. So all these are apparent in the measured voltage. So, again not to :dead_horse: ...well, you get the idea, but I still have a few questions about this. So, an amp that measures the same MUST sound the same, but no 2 amps sound the same due to variances that cause the voltage to be different...correct? With that said, if I am looking at amps from 2 or 3 different companies, do I trust the manufacturer specs that are either unreliable or derived under different conditions/testing methods, or just assume (I hate the meaning of that word) that any difference would be below the threshold of human hearing and that they would sound/perform the same, since I cannot afford to buy them all and test myself? I mean, if I eq a 6dB increase at 1K, do I "assume" every amp I am considering will handle this appropriately? If everything else is the same, do I look for the amp with the most power or largest headroom?


Mark has already covered this pretty well, but here's my take :

If by "variances" you mean the true noise (thermal, shot, flicker), then yes ... two voltages will never be identical to the smallest pico-volt. But as MarkZ said, that doesn't matter ... if the noise floor of each amp in comparison is "satisfactorily low", then it won't matter if they differ by a billionth of a volt.

If by "variances" you mean the slight errors in gain or frequency response, then again ... if the differences are below about 0.25 dB, it won't matter if one amplifier's voltage gain is 20.5729dB and the other is 20.5727dB.

Now, you DO raise an excellent point : Let's say we finally agree that two amps which measure the same, by delivering the same voltage (to within reasonable limits), have no choice but to make a loudspeaker react the same, and therefore "sound" the same ... whose measurements do we trust?

The first point to realize, is how far "ahead of the game" we already are, compared to purely subjective comparisons & reviews ... which depend on whose ears are listening, how truthful they are, how good their memories are, etc.

You *might* trust manufacturer's specs. You might trust a reputation, if the manufacturer has been around a long time. Or, you might look to work afoot to regulate, standardize and (presumably) punish for non-compliance. You might consider independent, third party measurements. Or ... you might start measuring yourself  the investment in learning and equipment might not be as bad as you think!

Wouldn't it be a great contribution to diyma, to have a measurement section for these electronic appliances, like we have a Klippel section for loudspeakers?


----------



## schmiddr2 (Aug 10, 2009)

lycan said:


> Wouldn't it be a great contribution to diyma, to have a measurement section for these electronic appliances, like we have a Klippel section for loudspeakers?


Yes. Maybe an Ampguts format but with detailed 3rd party measurements. Just the mention of this should scare the hell out of a lot of companies.


----------



## Niebur3 (Jul 11, 2008)

lycan said:


> Wouldn't it be a great contribution to diyma, to have a measurement section for these electronic appliances, like we have a Klippel section for loudspeakers?


Hey, this is like an episode of X-files....the truth is out there. Seriously, I may be up for something like that. I DON'T want to be ignorant on this subject and learning and teaching is the only way not to be. Unlike the midrange test, I will take a little time to think about what I am offering to make sure I am not in over my head, but I may be interested in helping the DIYMA community and perform these measurements at request.

In order to better make a decision on this, what would I need to get to be able to set up a proper test and is anyone willing to donate equipment to set something up, and if I ever find out it is too much time, it can go to the next person that volunteers - kind of like the Kippel? Just a thought!


----------



## schmiddr2 (Aug 10, 2009)

Niebur3 said:


> Hey, this is like an episode of X-files....the truth is out there. Seriously, I may be up for something like that. I DON'T want to be ignorant on this subject and learning and teaching is the only way not to be. Unlike the midrange test, I will take a little time to think about what I am offering to make sure I am not in over my head, but I may be interested in helping the DIYMA community and perform these measurements at request.
> 
> In order to better make a decision on this, what would I need to get to be able to set up a proper test and is anyone willing to donate equipment to set something up, and if I ever find out it is too much time, it can go to the next person that volunteers - kind of like the Kippel? Just a thought!


Shouldn't it be easier to set up an test environment for amps compared to testing speakers.


----------



## thehatedguy (May 4, 2007)

<- hopes no one thinks he is serious about cable elevators and such.


----------



## thehatedguy (May 4, 2007)

Someone wants to loan me an AP1 setup, I'll be glad to do testing.


----------



## lycan (Dec 20, 2009)

thehatedguy said:


> <- hopes no one thinks he is serious about cable elevators and such.


ahhh but ...

the real question is, what discerning facilities do you use to determine if it's ******** or not?

hopefully this thread sheds some light on that


----------



## Niebur3 (Jul 11, 2008)

thehatedguy said:


> <- hopes no one thinks he is serious about cable elevators and such.


What are you talking about? Is this directed at me? Anyway, let me know if anyone would like me to set up a testing environment for amps or not?


----------



## lycan (Dec 20, 2009)

lycan said:


> ahhh but ...
> 
> the real question is, what discerning facilities do you use to determine if it's ******** or not?
> 
> hopefully this thread sheds some light on that


edit: er um, _faculties_ maybe? it's been a long day


----------



## 89grand (Nov 23, 2006)

If I played two completely different amps in the middle of a forest, would anyone hear them?


----------



## lycan (Dec 20, 2009)

89grand said:


> If I played two completely different amps in the middle of a forest, would anyone hear them?


are there speakers connected?

dat's a perty impotant peece a info rite dere i tink


----------



## lycan (Dec 20, 2009)

cuz ya really can't hear the amps

well, maybe the fans

sometimes the transformers buzz i suppose


----------



## 89grand (Nov 23, 2006)

lycan said:


> are there speakers connected?
> 
> dat's a perty impotant peece a info rite dere i tink



Speakers connected, but the polarity on both reversed.


----------



## gt6334a (Sep 9, 2010)

make sure power is connected :laugh:


----------



## Niebur3 (Jul 11, 2008)

So based on this thread, we should never ask again "what are the best sq amps", we should instead measure, test, and compare data to show which amp performs/measures the best and therefore the data will tell us which sounds best (which of course mean, doesn't sound at all due to being completely transparent) and why. I like it!!! Much better than because X told me so or my improper A/B's I have done in the past.

I have learned a ton (I hope others have as well) and thank MarkZ, Lycan, Manville and Andy and others for their insightful contribution! 

Now someone get to testing every amp so I know what to buy...lol!

Have we even touched on the effect of a good/bad pre-amp ?


----------



## Thoraudio (Aug 9, 2005)

lycan said:


> cuz ya really can't hear the amps
> 
> well, maybe the fans
> 
> sometimes the transformers buzz i suppose


I had a Rockford T8004 that you could hear music out of the transformer.


----------



## Thoraudio (Aug 9, 2005)

FWIW, I tested quite a few back in the old Momentum days at Soundillusions, but never had the right equipment to do anything other than basic measurements. 

I don't know if they can still be found, but Carsound used to have a bank of amp tests from years back, complete with resistive and reactive load power tests, thd+n, FR, etc..... it was a great resource but is probably 10 years out of date by now.


----------



## 89grand (Nov 23, 2006)

Niebur3 said:


> So based on this thread, we should never ask again "what are the best sq amps", we should instead measure, test, and compare data to show which amp performs/measures the best and therefore the data will tell us which sounds best (which of course mean, doesn't sound at all due to being completely transparent) and why. I like it!!! Much better than because X told me so or my improper A/B's I have done in the past.
> 
> I have learned a ton (I hope others have as well) and thank MarkZ, Lycan, Manville and Andy and others for their insightful contribution!
> 
> ...


Honestly, no I don't think any amps "stand out" as being better sounding than most other modern designed amps.

I truly think it comes down to just power output, size factor, processing power if you need it, and some degree of a reputation of not being an unreliable POS. But that's about it...in my opinion.

I will say there are brands I hate for no scientific reason that I will not own, but it's just a personal hate, it's not sound quality related.


----------



## sq_assasin (Nov 10, 2008)

89grand said:


> Speakers connected, but the polarity on both reversed.


Is it hunting season? Are there any tree stands around?


----------



## 89grand (Nov 23, 2006)

sq_assasin said:


> Is it hunting season? Are there any tree stands around?


It is Elk hunting season, and Game and Fish are setting up decoy traps for poachers. Temperatures are in the mid 50's during the day, and quite cold at night, at or below freezing. There are a few tree stands in the area, but the nearest one is 479 meters from the speakers front firing cones and 1081 meters from the dual rear firing ports for the speakers woofer. Speakers in question are old school 3 way Cerwin Vega VS120's, that have been broken in for 12,637 hours.


----------



## lycan (Dec 20, 2009)

Niebur3 said:


> So based on this thread, we should never ask again "what are the best sq amps", we should instead measure, test, and compare data to show which amp performs/measures the best and therefore the data will tell us which sounds best (which of course mean, doesn't sound at all due to being completely transparent) and why. I like it!!! Much better than because X told me so or my improper A/B's I have done in the past.
> 
> I have learned a ton (I hope others have as well) and thank MarkZ, Lycan, Manville and Andy and others for their insightful contribution!
> 
> ...


well said.

Preamps are even easier, though  they are electronic appliances also, with even easier loads. You won't find any mysteries to their sound, that the very same voltage measurements won't (or can't) uncover. But their "feature set" can of course be more complex, meaning more measurements ... but the underlying logical principles are the same.

But always remember ... there's still good reason to spend differently, or choose differently, even when it comes to power amplifiers. Size, power, cosmetics, features, warranty, efficiency ... these are all valid, logical considerations.


----------



## thehatedguy (May 4, 2007)

Just was having some humor and picking at lycan.

It would be easier to do listening here...I have home speakers that are 100 dB efficient, if there are differences to be heard, it will be much easier to hear with super sensitive speakers.

Not to mention, I have the king **** (IMO) amp here- the HSS Fidelity HT230 that has upgraded power and preamp tubes, teflon caps, etc. If tubes aren't your game, I have a pair of Monolithic class A monoblocks...and if class A isn't your bag of tea, I can pull a Brax X2000 out from the closet...or a modded Image Dynamics 700.2. Hell, with the Image amp we can roll opamps since I had the only opamp still left in the preamp socketed. And hopefully one of these days maybe a full range class D to play with.

But all of that is subjective stuff.

If I could crap an AP1, I could show objective data too.



Niebur3 said:


> What are you talking about? Is this directed at me? Anyway, let me know if anyone would like me to set up a testing environment for amps or not?


----------



## mosca (Oct 26, 2009)

lycan said:


> You *might* trust manufacturer's specs. You might trust a reputation, if the manufacturer has been around a long time. Or, you might look to work afoot to regulate, standardize and (presumably) punish for non-compliance. You might consider independent, third party measurements. Or ... you might start measuring yourself  the investment in learning and equipment might not be as bad as you think!


could you point/link some amplifier measuring instructions for non-engineers?

I've found this via Google Measuring Amplifiers - AVS Forum. is it good enough?


----------



## lycan (Dec 20, 2009)

In order for me to support any more discussion, or endorse a testing methodology for diyma ... we're gonna have a little quiz 

1. First question (posted earlier) :

"_Why must we compare amplifiers on the *same set* of speakers? I mean, that might be fine in your so-called "laboratory", but here in the REAL WORLD amplifiers drive different speakers all the time! Plus, the amplifiers do it in DIFFERENT cars! So all this "controlling variables" makes no sense, in the REAL world. I know amps sound different, because i listened to the Bangkracker in my 98 civic with Truesound speakers, and it sounded WAY different than the Nutbanger in my buddies 92 camaro with the ****spasms. A real-wolrd test ... and the amplifiers sounded WAY different!!! _"

What's the answer, or resolution, to this common complaint?

2. Second question :

"_Hey idiot, VOLTAGE doesn't tell the whole story. How about CURRENT, genius? What if the voltages to two identical loudspeakers are identical, but the currents aren't? You can bet your boots that those speakers will sound different! In fact, that's why I prefer high-current amplifiers!_"

Is this a valid issue?

Think you've got the concepts?  Make sure you understand this stuff ... and a few more questions about basic logic & electronics ... before you pull out the voltmeters


----------



## Thoraudio (Aug 9, 2005)

lycan said:


> In order for me to support any more discussion, or endorse a testing methodology for diyma ... we're gonna have a little quiz
> 
> 1. First question (posted earlier) :
> 
> ...


did somebody say current source amp?


----------



## thehatedguy (May 4, 2007)

Wasn't current source amps not allowed in the great amp challenge? Seems like I remember seeing that somewhere.



Thoraudio said:


> did somebody say current source amp?


----------



## Thoraudio (Aug 9, 2005)

thehatedguy said:


> Wasn't current source amps not allowed in the great amp challenge? Seems like I remember seeing that somewhere.


IIRC amps did have to be voltage source amps, which given the nature of a current source amp and a reactive speaker, they would be fairly obvious. 

But current source amps are super rare in the car...... was one of the Phass amps current source? or just a super high output impedance?


----------



## thehatedguy (May 4, 2007)

I think the top of the line Phass was/is a current source amp.


----------



## mosca (Oct 26, 2009)

lycan said:


> In order for me to support any more discussion, or endorse a testing methodology for diyma ... we're gonna have a little quiz
> 
> 1. First question (posted earlier) :
> 
> ...


I don't think I would have the patience to discuss anything with somebody that says this. I know that would no matter what I'd say, they would (and they do) keep throwing some other nonsense at me as the discussion evolves.

of course they thought the amp "sounded different"... the settings (gain, eq?) and the interface (speakers, car) with it were different too.

but how can we explain that to somebody who just does not understand this logical premise? (note: those might not be the best terms, my english is quite flawed).



lycan said:


> 2. Second question :
> 
> "_Hey idiot, VOLTAGE doesn't tell the whole story. How about CURRENT, genius? What if the voltages to two identical loudspeakers are identical, but the currents aren't? You can bet your boots that those speakers will sound different! In fact, that's why I prefer high-current amplifiers!_"
> 
> ...


if voltage and impedance are identical, then current should be identical too.

I didn't know about high-current amps (very new to this world) but found this on BCAE1 High Current Amplifiers:



> An amplifier designated as a high current amplifier is generally a class A/B amplifier which can drive a lower impedance load than the industry standard 2 ohms per channel. Some high current amplifiers can drive loads as low .5 ohms stereo or even .67 ohms mono (yikes!). This page will give a review of amplifier basics and will show some of the differences between standard and high current amplifiers.


now I have some very dummy questions:

1. does the impedance of a speaker drop below it's rated/measured spec while reproducing a signal?.

2. if it does drop, would a non-high-current amp enter in protect mode/shut down if the amp does not support that low impedance?.

3. if it does drop, would this push the amp into a perceptible distortion zone (i.e. clipping)? would this happen to an amp that does not change power on impedance (i.e. PDX, JL Audio)?.


----------



## kyheng (Jan 31, 2007)

Frequencies change the impedance


----------



## mosca (Oct 26, 2009)

kyheng said:


> Frequencies change the impedance


I understand speakers have impedance curves associated with their frequency response, but can the curves go below, not above, their typical stated impedance?. i.e if if is 2 ohm (1.6 ohm really or whatever it is) can it drop below this value?.


----------



## lycan (Dec 20, 2009)

mosca said:


> I don't think I would have the patience to discuss anything with somebody that says this. I know that would no matter what I'd say, they would (and they do) keep throwing some other nonsense at me as the discussion evolves.


Welcome to my world  But any aspiring testers better be ready ...


> of course they thought the amp "sounded different"... the settings (gain, eq?) and the interface (speakers, car) with it were different too.
> 
> but how can we explain that to somebody who just does not understand this logical premise? (note: those might not be the best terms, my english is quite flawed).


Your english is fine, and your logic is even better 

Yes ... the answer to my first "question" is this: In an UNCONTROLLED environment, you can't tell if the difference you heard was due to : amplifiers, speakers, gain settings, environment, etc. A laboratory IS the real world ... but it's a world where variables are ISOLATED and CONTROLLED so that cause & effect can be DETERMINED.

Want to compare two _different_ amps with two _different_ speakers? Fine, there's a way to do this too  But there's a way to do this, while STILL controlling variables so that the effect of each can be isolated. I'll leave that as an exercise to the reader (hint: you don't need the search function, what you need is a logical, reasoning mind).

Or, you can use a _reasonable approximation_ of most speaker loads when electrically testing amplifiers 


> if voltage and impedance are identical, then current should be identical too.


One correction, to your otherwise CORRECT answer of Question #2:
"If the voltage and impedance are identical, then current *WILL* be identical too."

This is basic Ohm's Law ... nothing more. If you don't understand this THROUGH & THROUGH, please stay far away from electronic equipment. The amplifier determines the voltage, and the speaker (by virtue of its impedance) determines the current. A so-called "high current" amplifier only means that it's _capable_ of delivering a high current, should the speaker's impedance drop low enough to demand it. It does NOT mean that the amplifier can somehow "choose" to deliver an identical voltage to an identical impedance with a "higher" current. If you don't understand this as readily as one plus one equals two, you're not ready to start measuring amplifiers.

A so-called "current source" amp is a different (mostly stupid) beast, but it still obeys Ohm's Law. The amplifier will determine the current, and the speaker's impedance will determine the voltage. A story for another day ...

Key point : an amplifier does NOT have "two degrees of freedom". It can pick one ... ususally voltage ... and the speaker's impedance will determine the other.


> I didn't know about high-current amps (very new to this world) but found this on BCAE1 High Current Amplifiers:


I'll return to your questions later today:


> now I have some very dummy questions:
> 
> 1. does the impedance of a speaker drop below it's rated/measured spec while reproducing a signal?.
> 
> ...


Seriously dudes, I'm NOT trying to discourage any testing. But any aspiring testers better know these kinds of things with ABSOLUTE CLARITY. It's mostly a question of logic & reasoning skills (all too absent in most audiophile circles), rather than electronic knowledge. But certainly knowing Ohm's Law will help


----------



## lycan (Dec 20, 2009)

mosca said:


> now I have some very dummy questions:


These are FAR from dumb questions !!


> 1. does the impedance of a speaker drop below it's rated/measured spec while reproducing a signal?.


OK ... this one might be *a little* dumb, but not really   You can't even _measure_ a speaker's impedance, without asking it to reproduce a signal ... even if that signal is small. Measuring an impedance means applying a voltage and measuring a current (or vice-versa). If there's (AC) current flowing, the speaker is moving ... and creating sound.

HOWEVER, a very valid question is this : of course, the impedance varies with _frequency_. This is a known, expected property of any linear system. BUT ... does the impedance vary with _signal level_ (amplitude)? Will I measure a different impedance curve, with a _large-signal_ frequency sweep versus a _small-signal_ frequency sweep? This is a characteristic of a NON-linear system. And the answer, for loudspeakers, is absolutely YES.

Now ... For large signals, will the impedance drop even lower (at *some* frequency) then the specified minimum value for "small signals"?

*I don't know* ... but it's a good, valid question 


> 2. if it does drop, would a non-high-current amp enter in protect mode/shut down if the amp does not support that low impedance?.


YES IT WILL .. because it must. Or perhaps, the voltage output will "sag" (rather than amp shut-down), because it can't support/supply the current demanded by the lower impedance.


> 3. if it does drop, would this push the amp into a perceptible distortion zone (i.e. clipping)? would this happen to an amp that does not change power on impedance (i.e. PDX, JL Audio)?.


A great question! Something i need to start another thread about.

*I don't understand LOAD REGULATION from the source (rather than the load). I don't understand how RIPS works, in the presence of a very reactive speaker impedance.

I'll say it again ... I understand supply regulation in a power amp. I do NOT understand "load regulation" from the source ... I do NOT understand how the source (amplifier) can SUCCESSFULLY regulate the power to the load (speaker). The load is "expecting" a flat, uniform voltage (for flat frequency response) from the amplifier. Therefore, the load is "expecting" the amplifier to supply whatever CURRENT ... and consequently, whatever POWER ... it demands. In short, the reactive load is expecting constant voltage, not constant power, as its reactive impedance VARIES.
*
 

A topic for another thread ...

But in the meantime ... and i'm sure this will cause some fire :

Are there measurable ... and sonic ... consequences to LOAD REGULATION from an amplifier (i still don't get that principle), while driving _very_ reactive loads? Compared, that is, to an amplifier that can behave like a voltage source, over the reactive impedance range?

I don't understand how the answer could be anything but YES


----------



## msmith (Nov 27, 2007)

The impedance cannot drop below DCR (DC Resistance) of the voice coil.

The way RIPS works is by monitoring output current at or near clipping and setting the rails accordingly. The amps starts at the highest rail voltage (allowing more power at high impedances than a conventional design), and ratchets down the rail voltage if certain current limits are exceeded, latching in that position until it is reset. Once RIPS sets the correct maximum rail voltage, it behaves like any other voltage source amplifier. In the case of a Class D, the PWM duty cycle and gain are manipulated to the same end.


----------



## lycan (Dec 20, 2009)

msmith said:


> The impedance cannot drop below DCR (DC Resistance) of the voice coil.
> 
> The way RIPS works is by monitoring output current at or near clipping and setting the rails accordingly. The amps starts at the highest rail voltage (allowing more power at high impedances than a conventional design), and ratchets down the rail voltage if certain current limits are exceeded, latching in that position until it is reset. Once RIPS sets the correct maximum rail voltage, it behaves like any other voltage source amplifier. In the case of a Class D, the PWM duty cycle and gain are manipulated to the same end.


i'll be starting a new thread  and i'll look forward to your input ! In the meantime, at what _frequency_ are these measurements made (sensing of current, while supplies are high, for example)? How does the amp "know" when/if it has really "captured" the impedance "extremes" of a reactive speaker?


----------



## MarkZ (Dec 5, 2005)

msmith said:


> The impedance cannot drop below DCR (DC Resistance) of the voice coil.
> 
> The way RIPS works is by monitoring output current at or near clipping and setting the rails accordingly. The amps starts at the highest rail voltage (allowing more power at high impedances than a conventional design), and ratchets down the rail voltage if certain current limits are exceeded, latching in that position until it is reset. Once RIPS sets the correct maximum rail voltage, it behaves like any other voltage source amplifier. In the case of a Class D, the PWM duty cycle and gain are manipulated to the same end.


How is this different from class G operation?


----------



## msmith (Nov 27, 2007)

MarkZ said:


> How is this different from class G operation?


Class G (and H) shift adjust rail voltage dynamically in response to the input signal. This is done to improve efficiency by not wasting energy with high rail voltages when they are not needed.


----------



## msmith (Nov 27, 2007)

cajunner said:


> forgive this elementary question, but how do you change rail voltage? I was under the impression that the number of turns around the toroid, dictates the step up in voltage and is a fixed, or un-changing variable...?


Well, it's a switching power supply, not a simple toroidal transformer. Without getting into too many details, we adjust the duty cycle and frequency of the PWM (pulse width modulator) to set the rail voltage that is appropriate to the load connected to the output.


----------



## MarkZ (Dec 5, 2005)

msmith said:


> Class G (and H) shift adjust rail voltage dynamically in response to the input signal. This is done to improve efficiency by not wasting energy with high rail voltages when they are not needed.


I don't see how your description of RIPS is different from class G or H (I don't know if it's a continuous adjustment or discrete values). Is it just an implementation of G or H? Or is RIPS only changing rail voltage with output current -- like a toned down overcurrent protection circuit?


----------



## lycan (Dec 20, 2009)

MarkZ said:


> I don't see how your description of RIPS is different from class G or H (I don't know if it's a continuous adjustment or discrete values). Is it just an implementation of G or H? Or is RIPS only changing rail voltage with output current -- like a toned down overcurrent protection circuit?


RIPS latches (sets & keeps) it's rail voltage selection. Class G dynamically alters it's rail voltage, continuously, for improved efficiency.

But .. i still don't understand RIPS 

I'll start a detailed thread later tonight ...


----------



## Thoraudio (Aug 9, 2005)

> A so-called "current source" amp is a different (mostly stupid) beast, but it still obeys Ohm's Law. The amplifier will determine the current, and the speaker's impedance will determine the voltage. A story for another day ...


You know us old dudes have to keep you on your toes. 



<- still thinks a current source amp would be great for SPL contests....


----------



## envisionelec (Dec 14, 2005)

MarkZ said:


> I don't see how your description of RIPS is different from class G or H (I don't know if it's a continuous adjustment or discrete values). Is it just an implementation of G or H? Or is RIPS only changing rail voltage with output current -- like a toned down overcurrent protection circuit?


Class G, H or others are entirely different. Class G is a stepped voltage switch system using comparators (usually only one step) that engages an upper set of transistors into the output when the requirement comes within, say 25V of the rail voltages. 

Class H uses a variable supply generated by a buck converter through a pair of inductors to modulate the rails 6-8 volts above the required output voltage. Carver Sunfire subwoofer "cube" does this.

I have no direct experience with JL RIPS, but it appears to be a variant of technology that was used in Soundstream Reference and Phoenix Gold M-Series amplifiers. SS used a comparator to monitor current draw from the rails to flip the PWM duty cycle to deliver lower rail voltage and preserve the switching components. PG appeared (I don't know for certain...just appearance) to monitor current draw on the secondary side through a pair of 10W resistors to drive a circuit which dynamically adjusted the PWM duty cycle. If it hit a certain current limit, the amp would illuminate its "overcurrent" LED and latch the PWM IC off. 

JL appears to be using yet another variant of this type of self-preservation by monitoring output vs rail voltage. Speakers aren't constant current devices and since you aren't give the option to calibrate the amplifier based on the speaker's impedance, there is no sure way for the amplifier to know what is happening. JL probably figured that people would try to cheat the system by connecting an 8 ohm driver and then wiring in their 1 ohm quad coil DDs. That causes small, smoky fires. However, the power supply can make an educated guess by monitoring _current slope._


----------



## envisionelec (Dec 14, 2005)

Thoraudio said:


> You know us old dudes have to keep you on your toes.
> 
> 
> 
> <- still thinks a current source amp would be great for SPL contests....


A current output amplifier has a (theoretically) infinite output impedance. I don't see how this would be a good thing...


----------



## thehatedguy (May 4, 2007)

I never understood why RIPS didn't go above 4 ohms. Very rarely does a speaker's impedance drops to DCR when it's playing, but always goes way above it. Seems like you would get more real power to the speaker if you had RIPS set to like 4-16 ohms in stereo.


----------



## thehatedguy (May 4, 2007)

It was first used in the PPI 2350DM. That amp did the same power into a few different impedances. And seeing who the engineer was who designed the PPI...you see where JL got it from. 



envisionelec said:


> I have no direct experience with JL RIPS, but it appears to be a variant of technology that was used in Soundstream Reference and Phoenix Gold M-Series amplifiers. SS used a comparator to monitor current draw from the rails to flip the PWM duty cycle to deliver lower rail voltage and preserve the switching components. PG appeared (I don't know for certain...just appearance) to monitor current draw on the secondary side through a pair of 10W resistors to drive a circuit which dynamically adjusted the PWM duty cycle. If it hit a certain current limit, the amp would illuminate its "overcurrent" LED and latch the PWM IC off.
> 
> JL appears to be using yet another variant of this type of self-preservation by monitoring output vs rail voltage. Speakers aren't constant current devices and since you aren't give the option to calibrate the amplifier based on the speaker's impedance, there is no sure way for the amplifier to know what is happening. JL probably figured that people would try to cheat the system by connecting an 8 ohm driver and then wiring in their 1 ohm quad coil DDs. That causes small, smoky fires. However, the power supply can make an educated guess by monitoring _current slope._


----------



## envisionelec (Dec 14, 2005)

thehatedguy said:


> It was first used in the PPI 2350AM. That amp did the same power into a few different impedances. And seeing who the engineer was who designed the PPI...you see where JL got it from.


 The technology isn't new. It has a new name. They gotta keep finding new ways to do the same sort of stuff. 

Though I suspect the 2350DM was simply a tightly regulated PWM based on voltage mode feedback. It did use a full bridge PWM though - one of, if not _the first_, to use a full bridge in the power supply.


----------



## MarkZ (Dec 5, 2005)

I know what G and H are. I'm still not sure I get this RIPS thing, although it sounds like what I said about a toned-down overcurrent thing. It's monitoring current draw (from where? across the emitter resistors like overcurrent protection?) and then, instead of muting it's reducing the PWM freq? Or is it switching to a different transformer tap?


----------



## Snails (Apr 23, 2010)

DS-21 said:


> I would say that the passion is misplaced then. For a consumer to be passionate about commodity signal-enlargers is frankly kind of weird. Certainly, it has nothing to do with the ostensible purpose of audio, which is to reproduce _music._
> 
> The whole point of *all* the gear, IMO, is to get out of the damn way of the music.
> 
> Nothing wrong with being passionate about making a better amp, mind. I assume your engineers, and those at PowerPhysics, are such people, and we're all better of for it. But those are also people who can see beauty and elegance and even gratification in "simple numbers and graphs."


Wow, you are passionate on this subject. No room for debate. Imagine if you caught the other side in a bold face lie!


----------



## envisionelec (Dec 14, 2005)

cajunner said:


> well,
> 
> Car Audio Amplifiers - Car Audio Amps - JL Audio
> 
> ...


I design SMPS - which is how I got into this car amplifier thing in the first place. I see exactly what they're doing to get their current draw requirements. Interestingly, I've got a design from 1996 that does the same thing. Does that mean I invented it? 

They've got a pair of toroidal cores functioning as current monitors on each leg of the power transformer's primary side. The topology is push pull, so there are two switched primary windings and a center tap held at battery voltage. The other two, horizontally mounted, stacked core toroids are secondary side inductors found in all regulated power supply designs. The little E-core yellow guy is probably the housekeeping PS transformer. Hmm, seems well made. So much for old school being better...this is really nice. 

What they do with this current measurement is left to speculation, but it's not rocket science.


----------



## sq_assasin (Nov 10, 2008)

If you think all amps and headunits sound the same, then chalk it up to God giving you a ****ty ass pair of ears. This hobby is not for you. 

For all that disagree, why don't you buy your amps at Wal-Mart? Thought so. Two faced ****ers.


----------



## rommelrommel (Apr 11, 2007)

sq_assasin said:


> If you think all amps and headunits sound the same, then chalk it up to God giving you a ****ty ass pair of ears. This hobby is not for you.
> 
> For all that disagree, why don't you buy your amps at Wal-Mart? Thought so. Two faced ****ers.




Not enough threads for you to troll? We've obviously <mostly> agreed that they can sound different... just that any difference is electrically measureable.


----------



## MarkZ (Dec 5, 2005)

I don't buy mine at Wal-mart. They're too expensive there.

I have a lot of flaws, but being two-faced isn't one of them. I've spent a grand total of about $50 on the amplifiers in my system.  [actually, I think it was less...] And they sound no different from anyone else's.


----------



## MarkZ (Dec 5, 2005)

Got one for free because it was just the board, and bought the other broken.


----------



## coyote-1 (Nov 2, 2010)

Physics dictates that no combo of gear, nor even any one single piece of gear, will achieve perfection in freq.response or distortion - or in any other spec. As an amp heats up, its characteristics change. What you measured after a half-hour of runtime will show differently after a full hour.

Throw 'em into a car, and talk of 'objective' goes (literally) out the window.


lycan said:


> So the question always remains : How do you know whether or not the difference you heard can be attributed to : gain, power, frequency response, noise or distortion?
> 
> How could anyone possibly answer this question? Do we have no choice but to wander aimlessly in the dark ... no choice but to rely on guru opinions and internet polls? Is there no logical process to determine if differences can be attributed to gain, power, frequency response, noise & distortion? What's the process to determine if these specs are indeed comprehensive?


That leaves us with the subjective experience. And there again, a car amp that has nearly flat response will sound sterile to someone used to using a quartet of KT88 tubes in his living room system.... and not only due to the usual confrimation bias present in us all. Configuring a system that sounds good to your ears, in your car, is really all that matters.


----------



## lycan (Dec 20, 2009)

coyote-1 said:


> Physics dictates that no combo of gear, nor even any one single piece of gear, will achieve perfection in freq.response or distortion - or in any other spec.


Fortunately, this statement has no more than academic interest. The human ear can't distinguish (for example) a "perfect" frequency response, from one that varies by +/- 0.25dB. Therefore, perfection need not be a goal in any piece of audio electronics ... and it need not be achieved, in order for two different pieces to be sonically indistinguishable.


> As an amp heats up, its characteristics change. What you measured after a half-hour of runtime will show differently after a full hour.


Not by much. The voltage gain of a feedback amp, for example, will be set by a RATIO of two resistors ... if those resistors are in close thermal proximity, you won't hear ... or measure ... significant thermal drift. I will grant you, though, that a low (or no) feedback, single ended, Class A triode amp _will_ drift with temperature.


> Throw 'em into a car, and talk of 'objective' goes (literally) out the window.


Nope. The physics of a car interior are NOT beyond objective analysis. An automobile environment is not somehow, mysteriously "beyond" the ability of science to understand & describe.

But that also doesn't matter. If two amps ... or headunits ... are sonically indistinguishable OUTSIDE the car, this means that the electrical signal created or passed by them are "close enough" for the ear to call them identical. Why would that _electrical_ property change, when i mount them in a car? (edit: except for alternator wine, of course. Certainly not beyond objective science to understand & solve!)


> That leaves us with the subjective experience. And there again, a car amp that has nearly flat response will sound sterile to someone used to using a quartet of KT88 tubes in his living room system.... and not only due to the usual confrimation bias present in us all. Configuring a system that sounds good to your ears, in your car, is really all that matters.


Well, some would argue that other things matter equally as much. Aren't you interested in knowing WHY something sounds good ... or bad? Even on a personal level, wouldn't you be interested in knowing if you can achieve the SAME sound, for LESS money or effort? On a social level ... beyond the personal, or subjective ... wouldn't you be interested in helping to teach others how to achieve satisfying results?


----------



## SoundChaser (Apr 3, 2009)

I swear that sometimes my system sounds different with absolutely no changes made. Is it due to temperature? Humidity? Time of day? Me being tired or more alert? Or maybe it’s just because that day I cleaned the **** out of my ears.


----------



## coyote-1 (Nov 2, 2010)

An analogy: I can go from Newark to NYC via the PATH train, or I can go via the Holland Tunnel. Both will take me to the exact same place, but I will encounter very different circumstances along the way. Likewise, two amps might produce identical output specs in a lab but, because they have used different components & arrangements to get to that point, be suceptible to different types of interference - or even have identical output at one operating temperature but varied output as they heat up.


lycan said:


> Fortunately, this statement has no more than academic interest. The human ear can't distinguish (for example) a "perfect" frequency response, from one that varies by +/- 0.25dB. Therefore, perfection need not be a goal in any piece of audio electronics ... and it need not be achieved, in order for two different pieces to be sonically indistinguishable.
> 
> Not by much. The voltage gain of a feedback amp, for example, will be set by a RATIO of two resistors ... if those resistors are in close thermal proximity, you won't hear ... or measure ... significant thermal drift. I will grant you, though, that a low (or no) feedback, single ended, Class A triode amp _will_ drift with temperature.
> Nope. The physics of a car interior are NOT beyond objective analysis. An automobile environment is not somehow, mysteriously "beyond" the ability of science to understand & describe.
> ...


I'm not claiming that auto interiors are beyond analysis. But you and I both know that the sound perceived in the driver's seat will be significantly different than what's perceived in the passenger-side rear seat. And seat position/tilt will also affect it since seats are not acoustically transparent, as will passenger and cargo load. Even a change in rearview mirror angle will change the reflections of sound in your car! Complete analysis would extend nearly into the infinite... that's why I said 'objective' analysis of such literally goes out the window.

Am I interested in knowing why something sounds as it does? You bet. Nothing I said earlier ought be constued as disinterest. I'm only saying that the experience of sound is an experience, and therefore mostly subjective since each of us hears differently. And experience doesn't always count in that regard IMO. I'm a musician, and I've run into many a soundman whose ears are destroyed from years of sitting at the board mixing too-loud concerts. lol


----------



## lycan (Dec 20, 2009)

The _electrical_ behavior of amps & headunits has nothing to do with subjective perception.

If two headunits, or amps, create the SAME electrical signal (as discussed, they don't have to be identical), then the SAME speakers have no choice but to create the SAME acoustic signal ... in ANY environment you choose.

Sure ... you can change seats in the car, or change the rearview mirror angle, and perceive a different sound. But that has nothing to do with the electrical signal created by a headunit or amplifier.

*If headunit A creates the same electrical signal as headunit B (to within the well established limits for sonic indifference), and you put these two headunits in the SAME physical environment, they simply have no choice but to sound the SAME. If you change the acoustic environment for one of them ... then the sound will surely be different! But that's NOT a difference in headunits* 

This is fundamental, scientific method stuff ... isolate variables, determine cause and effect, etc. All done to determine WHY things sound the way they do.

_music_ is emotion, _music_ is perception, _music_ is subjective ... but _audio_ is science, _audio_ is measurement, _audio_ is objective.


----------



## coyote-1 (Nov 2, 2010)

Only if their internal electrical path characteristics are also "the same".


lycan said:


> If two headunits, or amps, create the SAME electrical signal (as discussed, they don't have to be identical), then the SAME speakers have no choice but to create the SAME acoustic signal ... in ANY environment you choose.


Imagine this: One amp is a solid-state 'transistor' amp. The other is a tube amp.

The electrical output of each at a given frequency is identical in the lab, according to the specs you detailed (distortion, power, freq.response, noise, gain). So when we take each amp and put it in a car, the output ought be identical on that frequency, at least according to your statement. Right?

Not necessarily. Here's why.
Remember my statement about different paths?

The tube might be slightly *microphonic* at a totally unrelated frequency. It might pick up a particular frequency in the car's engine, and that might create a suboscillation that modulates the way the tube amplifies the reference frequency. So where the solid-state amp outputs the reference frequency identically to how it was output in the lab, the tube amp now outputs that frequency with a phase effect.

Granted this is an extreme example that we'd never find in an automotive amp.... but you could very easily find a class AB and a class D amp that put out virtually identical electrical output signals in the lab, yet display differences in behavior in a car.


----------



## lycan (Dec 20, 2009)

coyote-1 said:


> Only if their internal electrical path characteristics are also "the same".
> 
> Imagine this: One amp is a solid-state 'transistor' amp. The other is a tube amp.
> 
> ...


identical electrical paths are NOT required to produce indistinguishable sound. Two amps can _measure_ the same, in a given environment ... and therefore _sound_ the same in that environment ... even though the circuitry is VERY different. This is, really, the _whole point_ of scientific measurement ... if two amps, or headunits, measure the same electrically (power, gain, frequency response, noise & distortion) then they will sound the same ... no matter what circuit techniques are used.

But YES, i will grant you that vacuum tubes are subject to microphonics in a vibrating environment, that may be absent with transistors. One amplifier might have worse PSRR (power supply rejection ratio), so that a noisy power supply troubles one amp more than another. OR ... one amp has noise-cancelling/balanced inputs, whereas the other doesn't ... so a sonic difference may only show up in a noisy (ground loopy) environment.

I think it would be appropriate to say that the two pieces of audio electronics under comparison ... under measurement ... should be compared with the same power supply, and with the same input signals to really be a fair comparison 

I just want to avoid any confusion with the acoustic aspects of the environment ... seating position, proximity of drivers to reflecting surfaces, etc ... these will certainly impact the sound we perceive, but they won't make one headunit (or amp) sound different from another, if these two electrical appliances measure the same.


----------



## Killin'em (Sep 10, 2010)

Quality is something that can be heard. Because first you hear the sound then it travels along nerves to your brain where you make a DECISION on if it sounds good. The key here is the DECISION! If a person knows that an amplifier is cheap then that will effect the DECISION on how the music sounds to them. It will change the entire dynamic of the music so in that case YES they do sound different! I can admit that I fully believe there is a difference in the sound but I also agree that a resistor is a resistor and they may be made with the same wire.
A lot more goes into deciding if something sounds good then just "gain, power, frequency response, noise or distortion". I dont like Tupac. But I love Johny cash. They both have the same parts. Lungs throat lips ears arms and legs! I wouldn't like Johny Cash singing Tupac songs and I also wouldn't like Tupac singing Johnny Cash songs! So what do I like, the man or the songs? ....Neithier. I like what I like! and sometimes it is not based on "gain, power, frequency response, noise or distortion" 
Sometimes I will be flipping through the stations and I will hear a nice guitar riff and I will start bobbing my head but before too long I will hear "JESUS!!!" I realize I have stumbled upon a church station and I cant reach for the remote fast enough to change the station. Reason? I dont like church music. I have a predetermined opinion of the music and it sounds bad to me.
The same could be true of amplifiers. Maybe there is no difference. But I wont be tuning to the church channel any time soon. I also wont be running any Boss amps either. 
So if you believe there is no difference between amps. Go ahead and buy BOSS/pyramid/audio bahn. I may "hear" it and not know but when I see it I will see garbage. A lot of us are no longer adolescent but this is an adolescent hobby. and lets all be honest. In our playground NIKE'S ARE NOT NIKE'S WITHOUT THE SWOOSH!!". and cool kids dont sport ked's no matter how cheap you got'em or how comfortable you say they are! 

sound is also not the only variable. Nikes last for ever. Keds fall apart!
congrats to me on my 100th post


----------



## lycan (Dec 20, 2009)

Killin'em said:


> Quality is something that can be heard. Because first you hear the sound then it travels along nerves to your brain where you make a DECISION on if it sounds good. The key here is the DECISION! If a person knows that an amplifier is cheap then that will effect the DECISION on how the music sounds to them. It will change the entire dynamic of the music so in that case YES they do sound different! I can admit that I fully believe there is a difference in the sound but I also agree that a resistor is a resistor and they may be made with the same wire.
> A lot more goes into deciding if something sounds good then just "gain, power, frequency response, noise or distortion". I dont like Tupac. But I love Johny cash. They both have the same parts. Lungs throat lips ears arms and legs! I wouldn't like Johny Cash singing Tupac songs and I also wouldn't like Tupac singing Johnny Cash songs! So what do I like, the man or the songs? ....Neithier. I like what I like! and sometimes it is not based on "gain, power, frequency response, noise or distortion"
> Sometimes I will be flipping through the stations and I will hear a nice guitar riff and I will start bobbing my head but before too long I will hear "JESUS!!!" I realize I have stumbled upon a church station and I cant reach for the remote fast enough to change the station. Reason? I dont like church music. I have a predetermined opinion of the music and it sounds bad to me.
> The same could be true of amplifiers. Maybe there is no difference. But I wont be tuning to the church channel any time soon. I also wont be running any Boss amps either.
> ...


you're confusing _music_ ... and your personal "taste" of it ... with the electro-mechanical-acoustic chain that _reproduces_ it.

If two reproduction chains produce identical SPL's, for all frequencies, at your ear canals ... johnny cash will be reproduced the SAME by BOTH of them. So will church music. So will tupac.

Some like cash, some like tupac. No problem! That's a _subjective_ question, of personal taste ... and it has nothing to do with the SCIENCE of music REPRODUCTION, which is a question of _objective_ analysis & measurement.

Remember ... your power amplifier isn't "CREATING" those rich harmonic overtones of the bass guitar, or male voice. But if it has enough *power*, flat *frequency response*, and low *noise & distortion* ... it will RECREATE them faithfully & accurately


----------



## Cruzer (Jul 16, 2010)

cajunner said:


> one reason that you might have a changing response in car, is that your voltage regulator determines when your battery is sufficiently charged, and instead of boiling the electrolyte by staying at 14.4V the voltage is tapered back suddenly to 13.6V, creating a change in unregulated power supplies that at listening levels, equates to a 1.3 db level change across the bandwidth...


but ive seen multiple people say u cant hear a difference between 500 and 700 watts, or 1000 watts and 1200 watts.

maybe they are wrong then because ur saying u can hear the 1.3 db change


----------



## Cruzer (Jul 16, 2010)

generally i have seen people say that with sub power, but its still a 1-2 db difference in some cases and they say u cant hear it.

again this is just what ive read, i didnt say it


----------



## coyote-1 (Nov 2, 2010)

That is why I love double-blind tests. They take away the entire "Am I liking the one I'm supposed to like?" issue, and get down to the subjective experience - which is where it's at anyway. When you walk in to a speaker showroom, you ought go with a blindfold - and a person who knows nothing about audio to push button A, button B, etc. Make your speaker selection. Then do likewise with the amps.

In reference to lycan's "groping in the dark" metaphor, the double-blind would shine the light. We grope in the dark because the combo of sales incentive for the salesman and peer pressure prevents us from trusting our ears.


Killin'em said:


> Quality is something that can be heard. Because first you hear the sound then it travels along nerves to your brain where you make a DECISION on if it sounds good. The key here is the DECISION! If a person knows that an amplifier is cheap then that will effect the DECISION on how the music sounds to them. It will change the entire dynamic of the music so in that case YES they do sound different!


----------



## Cruzer (Jul 16, 2010)

cajunner said:


> have you ever tried playing pink noise and just moving an equalizer slider up 1 db on the range?
> 
> you can barely hear the change.
> 
> ...


like i said, thats just what i have read, i didnt make the statement.

i just went from 60x2 to 160x2 and i hear a huge difference in the 1 minute and 30 seconds i listened to it.


----------



## lycan (Dec 20, 2009)

cajunner said:


> one of the bigger things that affect a person's enjoyment of their music reproduction system, is seat angle.
> 
> when you tilt back, you place more weight against your back, instead of pivoting on your hips, you lay more weight along the spine, which places greater pressure on the seat-back, giving it more mass.
> 
> ...


and the effect will be _identical_ ... for two headunits that measure _identically_ (to within limits of sonic indifference) 

Of course, you're free to change your seat position with headunit B, while comparing to headunit A  but it would be a mistake to conclude that the difference is because of the "headunit SQ"


----------



## t3sn4f2 (Jan 3, 2007)

cajunner said:


> one reason that you might have a changing response in car, is that your voltage regulator determines when your battery is sufficiently charged, and instead of boiling the electrolyte by staying at 14.4V the voltage is tapered back suddenly to 13.6V, creating a change in unregulated power supplies that at listening levels, equates to a 1.3 db level change across the bandwidth...


Doesn't that essentially mean that there is 1.3dB of dynamic compression on the peaks? Is that audible the way that a 1.3dB change in absolute level is?


----------



## t3sn4f2 (Jan 3, 2007)

Thanks to ItalynStylion for bringing this up on another forum.


----------



## saber (Dec 28, 2010)

t3sn4f2 said:


> Thanks to ItalynStylion for bringing this up on another forum.


Interesting vid, thanks for posting!


----------



## Cruzer (Jul 16, 2010)

t3sn4f2 said:


> Thanks to ItalynStylion for bringing this up on another forum.


its been a while since i watched it, couple months, i liked it and agreed. but did it say anything about amps? i remember it talking about home receivers and some of the tuning on them


----------



## Speakers4Weapons (Jan 3, 2011)

lycan said:


> If you had read and _understood_ this thread  then you would readily accept that a person could _easily_ pick out his Milbert tube amp in an amplifier comparison ... but the reason *WHY* is because of the tube amplifier's gain, power, frequency response (probably), noise or distortion (equally probable)
> 
> I'll repeat it for the miliionth time : All amps do NOT sound the same. I can pull two amps from the same damn production line, and set their gains or crossovers different, and i promise they WILL sound different. *It's astonishing to me that nobody understands this.*
> 
> ...


Well ANY 2 of the same type amp will sound different from each other when using a different crossover setting on each one. Only cause you are messing with the slopes and cut offs of the amp. 
BUT when you have 2 amps, same brand. Same model. Same parts inside, they always sound the same. Thinking they sound different is crazy. If they do its cause parts were not the same in the amps or ohms load was different.
Id have to say that overall amps DO sound different by brand. but its pretty hard to sit there in a blind A/B test and name what amp you are listening too without even having a hint as to what brand. Its just to hard to do. Not impossible though. You would have to use the amps tested in the comparison OFTEN. And the comparison would be very hard especially when using speakers you arent use to listening too.
More than anything I can tell the difference between a Class A. class A/B and CLass D. The Class D is a big difference from the others. But when comparing Class D with another Class d then it gets pretty hard. Some amps Do have a certain sound. JL amps in my opinion have a certain depth to there Class D amps others dont. I think its cause they use a special bass enhancement circuit. Class A just stands out in highs more than any other class. 
When going from a cheap Jenson to a SoundStream Picasso you 100% with out a doubt hear a difference. But if you compare 2 Picasso's in the same line you wont hear any difference. That is unless one amp is malfunctioning or in a different ohm load or has different inside parts.


----------



## Speakers4Weapons (Jan 3, 2011)

Cruzer said:


> its been a while since i watched it, couple months, i liked it and agreed. but did it say anything about amps? i remember it talking about home receivers and some of the tuning on them


How the hell do you upload an hour of video on youtube? ( just watched the video )


----------



## Cruzer (Jul 16, 2010)

Speakers4Weapons said:


> How the hell do you upload an hour of video on youtube? ( just watched the video )


probably paid for it, just a guess tho


----------



## jsolares (Jul 31, 2009)

Cruzer said:


> its been a while since i watched it, couple months, i liked it and agreed. but did it say anything about amps? i remember it talking about home receivers and some of the tuning on them


it basically says that if the amps are transparent they will sound the same (< 1% Distortion, 100db SNR i think, flat eq), i just saw it and it doesn't talk about home receivers or tuning at all.


----------



## subwoofery (Nov 9, 2008)

thehatedguy said:


> Re power supplies...
> 
> The answer is...it depends. how close are you going to be to clipping? The one with the larger power supply could probably handle large transient dynamic swings better than the smaller one. Can you hear it? How loud are you listening and how close to clipping are you?
> 
> And Jeff picking on the AC coupling caps...poor guys. That's why they should be removed from the circuit...can't pick on what's not there .


Would like to have an explanation about something... 

1 amp has a small power supply that can do 100rms @ 1% distorsion. The other has a much bigger power supply that can do 200rms @ 1% distorsion. 
Let's say you set the gain and level match curves on both amps. And let's assume both amp, when set for 75rms, have a distorsion figure of 0.5%...

How can you measure dynamic peaks and power reserve? Since both amps have the same curve and do not output close to their max rating, is it safe to assume that both of those amps still sound the same?

Thanks a lot, 
Kelvin


----------



## envisionelec (Dec 14, 2005)

subwoofery said:


> Would like to have an explanation about something...
> 
> 1 amp has a small power supply that can do 100rms @ 1% distorsion. The other has a much bigger power supply that can do 200rms @ 1% distorsion.
> Let's say you set the gain and level match curves on both amps. And let's assume both amp, when set for 75rms, have a distorsion figure of 0.5%...
> ...


Amp #2 won't reach 200W if you set the gain the same as that on amp #1. When Amplifier #1 clips, amplifier #2 still has 2dB to go before it, too, clips. 

Dynamic power output is an entirely separate matter. It is done by sending the DUT (device under test) a few cycles (20mS burst) of 1kHz signal at the same drive level you used to measure maximum output at clipping. An amplifier will output either exactly the same power or slightly more, measured in dB, and designated as "dB headroom".

Headroom shouldn't be the deciding factor in comparing amplifiers, though, because a well designed amplifier will produce the same amount of power continuously or during peaks. This is because a properly dimensioned power supply will deliver_ all of the current all the time_. But, most amplifiers use power supplies that are designed to produce maximum power output for short amounts of time and thus actually have "reserve capacity". But when you think about it - do you really want an amplifier that only gives you _some_ of the power you paid for _some_ of the time?

I recently designed an amplifier that measures just 5x6x2" and delivers 250W per channel continuously. And by continuous I mean 20-20kHz white noise into 4 ohms for an hour straight with no signs of stress (or forced air cooling). I then decided to do an IHF-202 test (20mS at 1kHz) and I got the same output - because the power supply is designed to give the customer all of the power at any given time.

Oh yeah, I'm still building tiny amplifiers that kick ass, in case you're wondering.


----------



## subwoofery (Nov 9, 2008)

envisionelec said:


> Amp #2 won't reach 200W if you set the gain the same as that on amp #1. When Amplifier #1 clips, amplifier #2 still has 2dB to go before it, too, clips.
> 
> Dynamic power output is an entirely separate matter. It is done by sending the DUT (device under test) a few cycles (20mS burst) of 1kHz signal at the same drive level you used to measure maximum output at clipping. An amplifier will output either exactly the same power or slightly more, measured in dB, and designated as "dB headroom".
> 
> ...


Thanks for the explanation.  

What I really wanted to know is what really is headroom (a power supply+output stage that is more powerful than needed) and how to measure/compare it. 
Since both amps are set so they don't clip and have equal freq curves, we can assume they sound the same. Yet 1 amp still have reserve power and can output even more power for dynamic peaks. 
So can you REALLY say that those 2 amps WILL sound the same? 

Also would like to have more info regarding your *bold* statement... Regulated VS unregulated? From your post, it seems to be a totally different matter. Thanks  

Kelvin


----------



## 93accordlxwhite (Apr 29, 2011)

Wow this is a pretty interesting thread. Thanks OP, I'm looking for a headunit and really wonder sometimes when reading reviews how much is actual discernible difference. What I can't understand is that it seems that EQ settings will not translate exactly between different models so I don't know how someone can compare the 'sound' of the original deck.


----------



## sswanny_1 (Oct 23, 2011)

subwoofery said:


> Thanks for the explanation.
> 
> What I really wanted to know is what really is headroom (a power supply+output stage that is more powerful than needed) and how to measure/compare it.
> Since both amps are set so they don't clip and have equal freq curves, we can assume they sound the same. Yet 1 amp still have reserve power and can output even more power for dynamic peaks.
> ...


If both amplifiers never clip at any time during transient peaks, then theoretically the extra power would not be noticed. However, components from different manufacturers can and do sound different. That is the case with home audio as well.


----------



## Oliver (Jun 25, 2007)

sswanny_1 said:


> If both amplifiers never clip at any time during transient peaks, then theoretically the extra power would not be noticed. However, *components from different manufacturers can and do sound different.* That is the case with home audio as well.


*OK, on that *


----------

