# 4 Ohms Sub sounds better for SQ ?



## lehelke3

Is it just me or what the title says is really true.
I always had a nice SQ sub (Hertz Mille 15 and Focal KX46 now 40) and Audison VRX 1.500 or Voce 5.1 or Mosconi 100.2 bridged) and I tend to believe that when I had lower impedance the sound was harsher and muddied????

I could be wrong i'm just trying to figure out if this is true or not? 
What do you guys think ?

I personally like the sharp tight clean punchy bass for my music (trance and dance) as opposed to the mushy muddy and distortion sounding low bass (hip hop and rap)


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## DC/Hertz

It's all in your head. A good amp will still be under 1% TDH even under 1ohm. 
When you had the 2 channel bridged each channel was at 2ohm.


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## lehelke3

I hope so, because from what I remember when I was testing for this year's ago I DID hear a difference i'm just not sure anymore


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## gijoe

You thought you heard a difference, or the difference was because of something else. 

Also, hip hop and rap sound much better with good bass, muddy, distorted bass is from a bunch of kids with terrible systems. Get your substage right and listen to Dr. Dre's 2001 and you'll see how good rap can sound.


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## fish

gijoe said:


> You thought you heard a difference, or the difference was because of something else.
> 
> Also, hip hop and rap sound much better with good bass, muddy, distorted bass is from a bunch of kids with terrible systems. Get your substage right and listen to Dr. Dre's 2001 and you'll see how good rap can sound.


IMO, The best produced rap album ever. Very clean.


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## Elektra

Doesn't your damping factor reduce every time you drop the impedance? Also running a amp at a easier load helps with other issues like heat, current etc... unless your trying to hit numbers a decent amp that does 500+ at 4ohms bridged is 9/10 times plenty - if you need more power rather buy a bigger amp? 

Sometimes having 2 amps drive 2 subs works out better - as some amps don't double the power from 4ohms bridged to 2ohms bridged so you get more power to each driver with 2 amps and you keep your load easier

Dunno... that's my take - also depends on what you want out of your system as well I suppose


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## Hillbilly SQ

I won't run any amp below 2 ohms even if it's stable to 1 ohm. No good reason other than a mental one. Power is cheap these days and you don't have to buy expensive amps to get great sound especially when that amp is for a subwoofer. Buy an oversized amp and run it at 4 ohms and be happy. 4 out of the 5 subs in my collection are either d2 or single 4 so 4 ohms is all my 1 ohm stable amp will ever see. Just how it worked out.


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## kyheng

Don't bother much on a driver's impedance load. Sometimes I do believe that running higher than 4ohm at 8ohm sound more superior than running at 1, 2 or 4ohm. But again, it is just a busted myth.
Running higher ohm load will reduce the amp's output while running lower ohm load will make more heat on the amp.
The more important point is, running your amp at higher efficiency will be better.


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## ssclassa60

fish said:


> IMO, The best produced rap album ever. Very clean.




In the same vein, Snoop's Doggystyle is up there too


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## fish

I prefer 4 ohms when possible, but that's not always the case. I'm about to run my sub(s) @ 1 ohm for the first time, & I'm a little concerned about the amp (MMATS HiFi6150d) overheating. Time will tell...


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## ssclassa60

Throw a fan on it 
I ran cheater amps at 1ohm bridged back in the day. A couple of 100cfm fans kept things reliable. I still have those amps and they still sound great (SS Class A 6.0s)


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## syc0path

Elektra said:


> Doesn't your damping factor reduce every time you drop the impedance?


Yep, and that's the biggest issue in terms of making your bass sound sloppy. Speakers are piezoelectric. That's a fancy word meaning that not only does electricity make them move, but moving them generates electricity. 

A speaker's cone has mass, and therefore it has inertia. When it's moving in a given direction, it tends to keep moving in that direction. This momentum actually generates electricity, and the amp must overcome this electricity (called "back EMF") to start the cone moving in the other direction.

And just as a speaker wired at 2ohms draws more power from an amp that a speaker at 4ohms, a speaker at 2ohms generates more back EMF than a speaker at 4ohms.

Getting the cone to change directions quickly and crisply is an important key in creating tight, punchy bass. And running at a lower ohm load makes it tougher for the amp to do that.


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## DC/Hertz

Butler has shown how little the amplifiers damping factor effects it. 
His test shown it didn't make any difference until it reached single digits.


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## rc10mike

I experimented with different sub/amp setups for about 10 years. FWIW, I always enjoyed the higher ohm setups more, they just sounded better.


They also have amps with adjustable damping factor.


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## nhtunes

I am no expert but 500 watts at 2 ohms is not the same as 500 watts at 4 ohms.


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## Jepalan

syc0path said:


> Yep, and that's the biggest issue in terms of making your bass sound sloppy. Speakers are piezoelectric. That's a fancy word meaning that not only does electricity make them move, but moving them generates electricity.
> 
> A speaker's cone has mass, and therefore it has inertia. When it's moving in a given direction, it tends to keep moving in that direction. This momentum actually generates electricity, and the amp must overcome this electricity (called "back EMF") to start the cone moving in the other direction.
> 
> And just as a speaker wired at 2ohms draws more power from an amp that a speaker at 4ohms, a speaker at 2ohms generates more back EMF than a speaker at 4ohms.
> 
> Getting the cone to change directions quickly and crisply is an important key in creating tight, punchy bass. And running at a lower ohm load makes it tougher for the amp to do that.


Before we go down the damping factor rat-hole, here is another perspective...
https://www.rubyservsales.com/myth-busting-damping-factor-a-misunderstood-rating/

I would pay attention to the quote from Andy W in the above link.

And for what it is worth, "piezoelectric" is a term most commonly used to refer to a specific electrical property of certain materials. Most speakers are not "piezoelectric" by common definition (some tweeters are). However, it is true that cone/magnet motion can generate electric current in the voice coil (aka 'back-EMF').


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## dgage

nhtunes said:


> I am no expert but 500 watts at 2 ohms is not the same as 500 watts at 4 ohms.


From a speaker/subwoofer perspective there is no practical difference. 

For my commercial home theater subwoofers, I run them at 2 ohms and for subs that share an amp, each sub driver runs at 2 ohms so the amp sees a 1 ohm load (SpeakerPower amps). No difference in sound quality or any other measurable difference other than the subs have reduced volume because each sub is getting 2000w instead of the full 4000w. And I have a $1300 Earthworks M50 measuring mic with a $1500 MOTU microphone preamp to do the measurements.

EDIT: For this discussion, I don't think there is any difference between running a sub at 1/2/4/8 ohms etc with a quality amp that is designed for those low impedance loads. Good luck measuring a difference much less hearing a difference. Also, many amps put out more power at 2 ohms so if you stick to 4 ohms only, you're leaving power on the table for, in my opinion, no good reason. But don't worry, you'll have plenty of company in the audiophile mystics club.


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## dgage

I'd also like to point out the comparison that is being discussed here, 4 better than 2 ohms is an old discussion. The previous audiophile discussion was is 8 ohm better than 4 ohm and for the longest time home audiophiles wouldn't run lower than 8 ohm speakers. To me, that audiophile myth is the same as this discussion of 4 vs 2. Amps, if designed for it, are quite capable of running at 2 amps, and some even at 1 ohms.


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## DC/Hertz

Taking rise into account many well built amps won't have any issues running .25ohm. 
But you need to know your rise before you try it. 
Sure THD levels go up but then it's a question of is it audible. Normally the answer is no in sub bass


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## ChrisB

fish said:


> I prefer 4 ohms when possible, but that's not always the case. I'm about to run my sub(s) @ 1 ohm for the first time, & I'm a little concerned about the amp (MMATS HiFi6150d) overheating. Time will tell...


Mine never overheated at 1 ohm. 



ssclassa60 said:


> Throw a fan on it
> I ran cheater amps at 1ohm bridged back in the day. A couple of 100cfm fans kept things reliable. I still have those amps and they still sound great (SS Class A 6.0s)


1. It already has a fan on it
2. Full-Range class D is a completely different animal from your SS Class A 6.0 amplifiers


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## fish

Thanks for the reassurance Chris!


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## Alrojoca

Behind the myth, there was some confusion and technical talk or terms that made it confusing on the other thread 8 vs 4.


In most cases the higher load coil or combined coils subs were more sensitive meaning, the extra power at the lower impedance was not going to make up the difference being 2-3 db's. 

And someone said that dual coil subs, did not benefit from from wiring at a higher impedance or even if wired in series, the amp will still see 4 instead of 8 ohms, or 4 instead of 2 ohms.
Maybe I missed something, again it was a long thread with many agreeing to it, and no conclusion and having to figure it out between the lines.


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## ChrisB

Am I the only one who remembers when DVC subs first came out and they were that way for "wiring options"? I tend to recall a local shop telling me that was so the subs could better match the impedance of the amplifier versus HAVING to wire both coils up in either series or parallel. 

My how times have changed, lol. I could have sworn both my JL Audio and Alpine owner's manuals for my subs insisted that both coils be wired or your warranty was void.


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## Alrojoca

gijoe said:


> You thought you heard a difference, or the difference was because of something else.
> 
> Also, hip hop and rap sound much better with good bass, muddy, distorted bass is from a bunch of kids with terrible systems. Get your substage right and listen to Dr. Dre's 2001 and you'll see how good rap can sound.


 I checked this DRe original 2001 cd today in my systems today, the funny thing is earlier i listened to the Far East movement dirty bass through a flash drive 320kbb file 

To me the Dirty bass cd sounded way better, It is only about a year and months old. The Dre sounds just OK, it was extremely Flat and midrangie in my opinion, I have some Jazz CD's that have better and cleaner bass than that, electric and acoustic bass, not computer synthesized bass, computer or quality synthesized bass, Brad Mehldau Mehliana Luxe track.
Sorry to disagree, it's clean and plays clean loud but that's it


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## dgage

Alrojoca said:


> Behind the myth, there was some confusion and technical talk or terms that made it confusing on the other thread 8 vs 4.


If you were referring to a specific thread on DIYMA, I was referring generically to the many discussions that discussed 8 vs 4 back in the day, many of which were in magazines and before the Internet took off. Like I said, an old mythical discussion.


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## Alrojoca

dgage said:


> If you were referring to a specific thread on DIYMA, I was referring generically to the many discussions that discussed 8 vs 4 back in the day, many of which were in magazines and before the Internet took off. Like I said, an old mythical discussion.



Thanks 
Just to cut to the chase then.

Lower impedance is better if the amp puts out more power and it can handle it.
8 ohms will be a bad match for most car audio amps?

In some cases, and dealing with car audio lower impedance 2-4 ohms.

For example sub X brand dual 4 coil has 90 db spl
Sub X same brand and model in dual 2ohm coil has 93 db spl 
We are going to wire The D4 in parallel for the lowest resistance and the D2 in series. Only one sub will be used, simply a choice to be made between the 2 subs.

Amp puts 500W at 4 ohm and 750W at 2 ohms.

Which sub will be better for the amp assuming the rest of the specs are identical between subs power handling is 800W. 
The D4 in parallel or the D2 in series? 



I read the first 5 pages and I failed to read the last pages on that thread except for the last 2.


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## Elektra

I think it's just better on your electrical system if you can keep it at 4ohms or a very efficient 8ohm driver - if you have dual subs running 2 amps to keep them at 4ohms may prove to be costly 


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## audiocholic

Elektra said:


> Doesn't your damping factor reduce every time you drop the impedance? Also running a amp at a easier load helps with other issues like heat, current etc... unless your trying to hit numbers a decent amp that does 500+ at 4ohms bridged is 9/10 times plenty - if you need more power rather buy a bigger amp?
> 
> Sometimes having 2 amps drive 2 subs works out better - as some amps don't double the power from 4ohms bridged to 2ohms bridged so you get more power to each driver with 2 amps and you keep your load easier
> 
> Dunno... that's my take - also depends on what you want out of your system as well I suppose
> 
> 
> Sent from my iPhone using Tapatalk






I'am no expert so please dont take my word as reference but up untill this week after recieving an email from Helix for a question I pointed out to them I believe I along others might have the damping factor all wrong.


please view the link below which is the manual for a Helix A1 amp, notice on the last page it states damping factor adjustment for part no:22

https://130.com.ua/manuals/en/Manual-Car-amplifier-Helix-A1-Competition.pdf



if you view it it states the higher the factor the more the bass the lesser and you achieve a warmer and more balanced sound.


I was shocked when I read that and sent an email directly to Helix as I all along thought the higher the factor the more control the better everything would be but turns out thats not the case


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## quickaudi07

To me it don't matter if its 1 ohm load, or 2 or 4 or 8 or 16. as long as you have enough of of power going in to the sub, as long as its clean power,,, thats all it matters... but I would go with 2 ohm or 4 ohm configuration if you have the amp that could put out the juice at that ohm load.


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## 156546

Damping factor is fake news. 

Energy in the speaker's motor is stored in the inductance and in the compliance of the suspension. Damping is the speed with which the stored energy is dissipated and as far as amplifier output impedance goes, it has very little to do with the flow of current from the speaker because it's in series with the speaker's DCR and the DCR is what regulates the flow of current.

So, damping factor is crap so long as the value is greater than about 10. It's a non-spec.


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## DC/Hertz

GotFrogs said:


> Damping factor is fake news.
> 
> Energy in the speaker's motor is stored in the inductance and in the compliance of the suspension. Damping is the speed with which the stored energy is dissipated and as far as amplifier output impedance goes, it has very little to do with the flow of current from the speaker because it's in series with the speaker's DCR and the DCR is what regulates the flow of current.
> 
> So, damping factor is crap so long as the value is greater than about 10. It's a non-spec.


Don't tell the old linear power fanboys this. Well you can and do but they don't care. 
One of them told me to come out to an MECA event to hear some of the best cars in the circuit. He doesn't think mine can sound good since I use class D amps. At LPs headquarters. I looked at past events all over the state and they hardly have any cars breaking a 80. When they do it's just a new judge scoring higher then he should. I know Rays truck doesn't score good at all.


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## PPI_GUY

What I have seen (in limited comparisons) is that older amplifiers 'can' sound worse at 2 ohm loads on the sub channel primarily due to their inability to store and/or supply power in loud, deep or very punchy musical passages. This may be due to a poor vehicle electrical system, the inefficiency of older class a/b design or a combination of both.
This problem doesn't seem to be as prevalent in newer class D amplifiers with moderate wattage. Probably because of their higher efficiency and lower electrical system demands.


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## _dieselguy

Good info here


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## DeltaB

GotFrogs said:


> Damping factor is fake news.
> 
> Energy in the speaker's motor is stored in the inductance and in the compliance of the suspension. Damping is the speed with which the stored energy is dissipated and as far as amplifier output impedance goes, it has very little to do with the flow of current from the speaker because it's in series with the speaker's DCR and the DCR is what regulates the flow of current.
> 
> So, damping factor is crap so long as the value is greater than about 10. It's a non-spec.


At 1kHz, your assertion is correct, but at 30Hz, not so fast... >100 is desired. To claim amplifier damping factor is "fake news" only reveals how little you really understand about this issue.

From Crown Audio Amplifier Engineers; "Loudspeakers have a mind of their own. You send them a signal and they add their own twist to it. They keep on vibrating after the signal has stopped, due to inertia. That's called "ringing" or "time smearing." In other words, the speaker produces sound waves that are not part of the original signal. Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope. When the kick-drum signal stops, the speaker continues to vibrate. The cone bounces back and forth in its suspension. So that nice, snappy kick drum turns into a boomy throb. Fortunately, a power amplifier can exert control over the loudspeaker and prevent ringing. Damping is the ability of a power amplifier to control loudspeaker motion. It's measured in Damping Factor, which is load impedance divided by amplifier output impedance. High damping factor equals tight bass."

The lower the impedance of load, the less ability of an amp to exert control over the cone's movement for damping purposes, so to answer the OP's Q, depending on the amplifiers output impedance, as a general rule of thumb, a 4 ohm voice coil impedance is better for control coupled to the same amp 2 ohm or oven worse, 1 ohm. Many Class D amps these days, if the output is correctly engineered, can provide as decent a damping factor as a Class A/B, however in lower cost designs, this is overlooked. (coupling at the output filter stage) Remember the driver is just a motor in reverse, and the load on it's coupled end can exert control over it's movement. DCR = DC, impedance = AC.


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## GreatLaBroski

DeltaB said:


> At 1kHz, your assertion is correct, but at 30Hz, not so fast... >100 is desired. To claim amplifier damping factor is "fake news" only reveals how little you really understand about this issue.


Bold move calling out Andy, but +sub for the reply. 

I appreciate a good discussion with opposing viewpoints.


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## dsquared

I guess a thread is never too old to dispute its contents .
Curious to see how this turns out.


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## DeltaB

GreatLaBroski said:


> Bold move calling out Andy, but +sub for the reply.
> 
> I appreciate a good discussion with opposing viewpoints.


I was at Altec-Lansing back before Mark IV Industries (owned Altec, EV, Dynacord, University Sound, Telex...) sold it off to the Chinese and dropped the Professional lines, and it doesn't take long with a pulse tone to an A2 VOT cabinet in the anechoic chamber to prove up the exact same thing Crown engineers stated.


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## GreatLaBroski

DeltaB said:


> I was at Altec-Lansing back before Mark IV Industries (owned Altec, EV, Dynacord, University Sound, Telex...) sold it off to the Chinese and dropped the Professional lines, and it doesn't take long with a pulse tone to an A2 cabinet in the anechoic chamber to prove up the exact same thing Crown engineers stated.


Nice. To be fair I think Andy was making the point that it's not enough of a change to make a audible difference either way. However I did the same research and ended up opting for a 4-ohm subwoofer myself based on the same reasoning you posted above. I'm hoping that we'll get to see some data-driven debates on this topic.


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## dcfis

Why not 8 ohm or 16 ohm?


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## bbfoto

dcfis said:


> Why not 8 ohm or 16 ohm?



Just think about Ohm's Law in its entirety, but with the limitations of a using 12VDC power supply.


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## DeltaB

bbfoto said:


> Just think about Ohm's Law in its entirety, but with the limitations of a using 12VDC power supply.


Source voltage really doesn't have anything to do with it, outside of the fact that if you don't have a power supply to step up voltages, you will be limited on the output power. The power supply in the amp will step up voltages to meet the requirements of the output devices on the rail. If it's on 120V AC, then it's stepped down and taken to DC to meet the same requirement. It's about the output device topology, not source voltage.

For a basic primer on auto audio electronics, visit here;

Basic Car Audio Electronics


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## SPLEclipse

If you knew anything about speakers (and specifically subwoofers) you'd quickly understand that the energy stored in the speaker's equivalent acoustic circuit is so overwhelmingly large that any difference in damping from the amp is almost irrelevant. Take into account the additional ringing from any other resonant component in the enclosure and there's always going to be a "lot" of ringing no matter what the amp is trying to do. That's the point GotFrogs (Andy) was making.


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## DeltaB

SPLEclipse said:


> If you knew anything about speakers (and specifically subwoofers) you'd quickly understand that the energy stored in the speaker's equivalent acoustic circuit is so overwhelmingly large that any difference in damping from the amp is almost irrelevant. Take into account the additional ringing from any other resonant component in the enclosure and there's always going to be a "lot" of ringing no matter what the amp is trying to do. That's the point GotFrogs (Andy) was making.


Then you might want to take a serious look at your design then. When at Altec, extensive testing was made in the 24 cubic feet 8182 sub system, (3182 18" 8 ohm driver) and was bundled with the SS 1270 amp specifically due to it's damping performance. I do know a little bit about what I'm saying here.

When you take the position like you have, I can only interpret that to mean, "I cannot control my design, therefore, it's irrelevant."


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## Red Saber

I e always thought the speaker played a much larger roll then the amp. I doubt there are many amps today that won’t fit the bill. 
I had a write up once that showed it not making a difference but I can’t find it. It had measurements.


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## DeltaB

Red Saber said:


> I e always thought the speaker played a much larger roll then the amp. I doubt there are many amps today that won’t fit the bill.
> I had a write up once that showed it not making a difference but I can’t find it. It had measurements.


The anechoic chamber tells no lies. it is what it is.


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## Pb82 Ronin

Subbing. Interesting discussion.


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## Red Saber

DeltaB said:


> The anechoic chamber tells no lies. it is what it is.


If you can match any install to a chamber I will give you my life as a servant


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## DeltaB

Red Saber said:


> If you can match any install to a chamber I will give you my life as a servant


Your comment is not germane to the conversation.


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## POLKAT

DeltaB said:


> Source voltage really doesn't have anything to do with it, outside of the fact that if you don't have a power supply to step up voltages, you will be limited on the output power. The power supply in the amp will step up voltages to meet the requirements of the output devices on the rail. If it's on 120V AC, then it's stepped down and taken to DC to meet the same requirement. It's about the output device topology, not source voltage.
> 
> For a basic primer on auto audio electronics, visit here;
> 
> Basic Car Audio Electronics





DeltaB said:


> Then you might want to take a serious look at your design then. When at Altec, extensive testing was made in the 24 cubic feet 8182 sub system, (3182 18" 8 ohm driver) and was bundled with the SS 1270 amp specifically due to it's damping performance. I do know a little bit about what I'm saying here.
> 
> When you take the position like you have, I can only interpret that to mean, "I cannot control my design, therefore, it's irrelevant."


Sorry, I can't help but point out the irony here, as futile as it may be...

Per your "basic primer" Basic Car Audio Electronics link above, section 99, Damping Factor, says: _"Some switching amplifiers like Class D amplifiers have a lower damping factor than their Class A/B counterparts because the output of the amplifier has to pass through an inductor. Since the inductor is wound with copper wire which has resistance (albeit a very low resistance), the damping factor is reduced. *Generally the lower damping factor is completely inaudible*._"


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## dcfis

bbfoto said:


> Just think about Ohm's Law in its entirety, but with the limitations of a using 12VDC power supply.


Are you talking about power? No consideration for sensitivity?


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## DeltaB

POLKAT said:


> Sorry, I can't help but point out the irony here, as futile as it may be...
> 
> Per your "basic primer" Basic Car Audio Electronics link above, section 99, Damping Factor, says: _"Some switching amplifiers like Class D amplifiers have a lower damping factor than their Class A/B counterparts because the output of the amplifier has to pass through an inductor. Since the inductor is wound with copper wire which has resistance (albeit a very low resistance), the damping factor is reduced. *Generally the lower damping factor is completely inaudible*._"


Class A/B can be rated as high as the thousands, however, you rarely can find this in Class D because of it's design. My Class D is rated >200 @ 4 ohm. It all depends, as I stated before, how the output circuit is designed, and on many Class D amps, this is overlooked or ignored. At low frequency >100 is preferred.

It doesn't provide any irony, what it does, is only to go to show why in usage of Class D, loading an amp @ 2 or 1 ohm will only decrease damping performance into undesirable levels, and at those loads can even make some amps become unstable. It's no different than tube amps based on transformer outputs, however, the valve amps naturally function in quasi Current-drive having a high output impedance with minimal damping. A small amount of negative feedback taken from one speaker terminal is fed back to the cathode of the first input valve. Feedback reduces the output impedance and introduces damping to control excessive Q resonance of the speaker. Valve amps are naturally noisy (hum) and negative feedback quietens the amplifier and marginally reduces measured distortion. Effectively implementing this type of control in Class D is what many designers overlook. It's why Class A/B SS amps shine so well at low frequency damping factor and driver control. 

History has been forgotten and there is little interest in reflecting on what was not understood during the transition from valve to solid-state technology in relationship to returning to an inductor in the output design. (the same holds true to low quality inductors in crossovers reducing DF) All that was required was a simple addition to the gain management of solid-state amps to enable Voltage to Current drive adjustment so the DF of speakers could be effectively managed.

So, we are back to the OP's Q, and having said that, it's always better for SQ to utilize 4 or 8 ohm driver load, than to attempt to utilize 2 or even worse 1 ohm loads, especially on Class D. It isn't about maximum power, it's about maximum control.


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## DeltaB

On a heavier note, here's a sub for all to glory. Get your Class D's ready for this little baby...


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## ChrisB

When it comes to cone control on a subwoofer, a servo will do more than damping factor ever will. Change my mind!


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## DeltaB

ChrisB said:


> When it comes to cone control on a subwoofer, a servo will do more than damping factor ever will. Change my mind!


What does that have to do with the OP's Q?


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## Holmz

DeltaB said:


> What does that have to do with the OP's Q?


Quite a lot I imagine.


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## ChrisB

DeltaB said:


> What does that have to do with the OP's Q?


You are the one bringing up damping factor and how it relates to SQ. So... batter up!

EDIT: This thread is also borderline necro status, so does it really matter what my answer has to do with the OP's question?

EDIT2: I'll just leave this here - https://www.butleraudio.com/damping1.php


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## DeltaB

ChrisB said:


> You are the one bringing up damping factor and how it relates to SQ. So... batter up!
> 
> EDIT: This thread is also borderline necro status, so does it really matter what my answer has to do with the OP's question?
> 
> EDIT2: I'll just leave this here - https://www.butleraudio.com/damping1.php


Quasi-experts in this forum abounds I see...

Butler's transformer based valve amps can have their own opinions, however, it isn't rational, especially when trying to compare output topology. Educate yourself on DF between topology (voltage vs. current) first.

Valve Amps: Valve verses Solid-state amps

On SS amps, you're right back to what Crown Amp Enginners clearly stated, which I quoted before;

From Crown Audio Amplifier Engineers; "Loudspeakers have a mind of their own. You send them a signal and they add their own twist to it. They keep on vibrating after the signal has stopped, due to inertia. That's called "ringing" or "time smearing." In other words, the speaker produces sound waves that are not part of the original signal. Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope. When the kick-drum signal stops, the speaker continues to vibrate. The cone bounces back and forth in its suspension. So that nice, snappy kick drum turns into a boomy throb. Fortunately, a power amplifier can exert control over the loudspeaker and prevent ringing. Damping is the ability of a power amplifier to control loudspeaker motion. It's measured in Damping Factor, which is load impedance divided by amplifier output impedance. High damping factor equals tight bass."

Go argue with the Engineers at Crown... Next?


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## Red Saber

DeltaB said:


> Quasi-experts in this forum abounds I see...
> 
> Butler's transformer based valve amps can have their own opinions, however, it isn't rational, especially when trying to compare output topology. Educate yourself on DF between topology (voltage vs. current) first.
> 
> Valve Amps: Valve verses Solid-state amps
> 
> On SS amps, you're right back to what Crown Amp Enginners clearly stated, which I quoted before;
> 
> From Crown Audio Amplifier Engineers; "Loudspeakers have a mind of their own. You send them a signal and they add their own twist to it. They keep on vibrating after the signal has stopped, due to inertia. That's called "ringing" or "time smearing." In other words, the speaker produces sound waves that are not part of the original signal. Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope. When the kick-drum signal stops, the speaker continues to vibrate. The cone bounces back and forth in its suspension. So that nice, snappy kick drum turns into a boomy throb. Fortunately, a power amplifier can exert control over the loudspeaker and prevent ringing. Damping is the ability of a power amplifier to control loudspeaker motion. It's measured in Damping Factor, which is load impedance divided by amplifier output impedance. High damping factor equals tight bass."
> 
> Go argue with the Engineers at Crown... Next?


Speaking of Quasi-experts. Isn’t the internet great, you can always find something that agrees with you. And a lot that don’t.


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## DeltaB

Red Saber said:


> Speaking of Quasi-experts. Isn’t the internet great, you can always find something that agrees with you. And a lot that don’t.


I said it before, and will again, the anechoic chamber doesn't lie. It is what it is.


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## ChrisB

I'll state this... I'd be willing to bet that I could predict the results of someone in an a/b/x listening test where they are subjected to a subwoofer amplifier with a damping factor of 50 and a damping factor of 100. Out of 100 people, 98 of them wouldn't be able to tell which amplifier they were listening to based on damping factor beyond any statistical significance of guessing. The other two outliers may be just that dang good OR that dang lucky. Regardless, chances are anyone reading this thread will be in the 98 people group who won't be able to tell, yet most will think they are the golden ear two without being able to tell yet alone repeat the results.

Now let's take this further with a car amplifier, where the damping factor spec used to be cheated by being measured at the circuit board, versus at the speaker leads, yet alone the speaker itself. Yeah, good luck with that spec making a huge difference in SQ when you don't even know where it is measured.

Back to my original comment when it comes to cone control, a properly designed and implemented servo will beat damping factor 7 days a week and twice on Sunday! It should also reduce subwoofer induced distortion from the cone movement itself. I was told that the Velodyne car audio servo subwoofer was one of the best, but they failed to take one variable into consideration with the cone position sensor.... The movement of the vehicle itself. It was great for an SQ competition, but in some instances, results could vary once the vehicle was in motion. Oddly, this was vehicle dependent as I knew two different people who used this setup and one claimed it was fine with the vehicle still or in motion whereas the other one said it only worked in his trailer queen SQ vehicle and driving made the sub vary...

Which brings me to my next point. We are talking about CAR AUDIO here, which is generally the absolute worst reproduction environment that anyone could ever want when it comes to audio... At least modern day digital processing is making it better for multi-listening positions and imaging, to some degree. Good luck getting your anechoic chamber response in a vehicle.


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## DeltaB

ChrisB said:


> I'll state this... I'd be willing to bet that I could predict the results of someone in an a/b/x listening test where they are subjected to a subwoofer amplifier with a damping factor of 50 and a damping factor of 100. Out of 100 people, 98 of them wouldn't be able to tell which amplifier they were listening to based on damping factor beyond any statistical significance of guessing. The other two outliers may be just that dang good OR that dang lucky. Regardless, chances are anyone reading this thread will be in the 98 people group who won't be able to tell, yet most will think they are the golden ear two without being able to tell yet alone repeat the results.
> 
> Now let's take this further with a car amplifier, where the damping factor spec used to be cheated by being measured at the circuit board, versus at the speaker leads, yet alone the speaker itself. Yeah, good luck with that spec making a huge difference in SQ when you don't even know where it is measured.
> 
> Back to my original comment when it comes to cone control, a properly designed and implemented servo will beat damping factor 7 days a week and twice on Sunday! It should also reduce subwoofer induced distortion from the cone movement itself. I was told that the Velodyne car audio servo subwoofer was one of the best, but they failed to take one variable into consideration with the cone position sensor.... The movement of the vehicle itself. It was great for an SQ competition, but in some instances, results could vary once the vehicle was in motion. Oddly, this was vehicle dependent as I knew two different people who used this setup and one claimed it was fine with the vehicle still or in motion whereas the other one said it only worked in his trailer queen SQ vehicle and driving made the sub vary...
> 
> Which brings me to my next point. We are talking about CAR AUDIO here, which is generally the absolute worst reproduction environment that anyone could ever want when it comes to audio... At least modern day digital processing is making it better for multi-listening positions and imaging, to some degree. Good luck getting your anechoic chamber response in a vehicle.


No one, including me, stated a vehicle was an echoic chamber. The assertion that testing in an anechoic environment to begin with, is somehow irrelevant or unsubstantiated to achieve solid results and the effects of beginning with the best design you can afford is beyond rational thought, and nothing more than rhetoric over issues you don't understand. and to play the subjective card of a/b listening tests is just as irrational. It's just that simple.


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## ca90ss

Is there a link to the testing Altec did? I'd like to see what the results were.


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## DeltaB

ca90ss said:


> Is there a link to the testing Altec did? I'd like to see what the results were.


The company was sold in 1998, and the archives were not released. In fact most of it was destroyed. And that's sad too... Some sales info and cabinet designs are out there in the public domain, but no testing results were ever allowed out, and would be considered trade secrets.


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## ChrisB

DeltaB said:


> No one, including me, stated a vehicle was an echoic chamber. The assertion that testing in an anechoic environment to begin with, is somehow irrelevant or unsubstantiated to achieve solid results and the effects of beginning with the best design you can afford is beyond rational thought, and nothing more than rhetoric over issues you don't understand. and to play the subjective card of a/b listening tests is just as irrational. It's just that simple.


So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.

But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away. 

I'm just saying there are other places to look if something sounds wonky besides damping factor.

Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums.


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## DeltaB

ChrisB said:


> So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.
> 
> But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away.
> 
> I'm just saying there are other places to look if something sounds wonky besides damping factor.
> 
> Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums.


When you try to throw enough crap on the wall, hoping some of will stick, you end up where you are. Out of one side of your argument, damping factor doesn't play any part, then out of the other side, you argue servo's will outperform DF that which you said was irrelevant. You can't have it both ways. And to try to introduce subjective listening tests, you only attempt to muddy the water with subjective results that no one can pin down. Why? Because it's all subjective to the listener, and not empirical data. This is why manufacturers test in controlled environments. I can hear it now, "don't use measuring equipment, especially calibrated equipment, because, yeah, that sounds like a volt..." Pure bovine scatology.

I've come to conclude you're simply wanting to argue for no other reason than to argue. Go save face with someone else.


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## ChrisB

DeltaB said:


> When you try to throw enough crap on the wall, hoping some of will stick, you end up where you are. Out of one side of your argument, damping factor doesn't play any part, then out of the other side, you argue servo's will outperform DF that which you said was irrelevant. You can't have it both ways. And to try to introduce subjective listening tests, you only attempt to muddy the water with subjective results that no one can pin down. Why? Because it's all subjective to the listener, and not empirical data. This is why manufacturers test in controlled environments. I can hear it now, "don't use measuring equipment, especially calibrated equipment, because, yeah, that sounds like a volt..." Pure bovine scatology.
> 
> I've come to conclude you're simply wanting to argue for no other reason than to argue. Go save face with someone else.


I'm pretty sure I haven't contradicted myself. I said if you wanted cone control, a server was where it was at. Only problem, good luck getting that in a car as no one makes them these days. OTOH, for the home front, both Velodyne and Rythmik are viable choices and well regarded.

When it comes to the worst reproduction environment known to man for audio, I'm of the school of thought that damping factor above the audible threshold where no one can tell a difference is a waste of time, money, and effort. If it makes a difference to YOU to spend money on something that has an advertised damping factor of 1,000 at the circuit board, by all means, SPEND YOUR MONEY. I'm saying look elsewhere! Besides, there is a law of diminishing returns where an exponential price increase in equipment may result in single digit to no percentage of satisfaction increase with swapping out gear.


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## dcfis

I solved the problem and got 2 8ohm subs. So 2 for one.


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## DeltaB

ChrisB said:


> I'm pretty sure I haven't contradicted myself. I said if you wanted cone control, a server was where it was at. Only problem, good luck getting that in a car as no one makes them these days. OTOH, for the home front, both Velodyne and Rythmik are viable choices and well regarded.
> 
> When it comes to the worst reproduction environment known to man for audio, I'm of the school of thought that damping factor above the audible threshold where no one can tell a difference is a waste of time, money, and effort. If it makes a difference to YOU to spend money on something that has an advertised damping factor of 1,000 at the circuit board, by all means, SPEND YOUR MONEY. I'm saying look elsewhere! Besides, there is a law of diminishing returns where an exponential price increase in equipment may result in single digit to no percentage of satisfaction increase with swapping out gear.


Again, you have missed the entirety of the conversation by the bias you seem to be unwilling to recognize. And that bias is based from inexperience. You're presenting extremes to attempt to prove a point that is not rational. I don't need 100 people to come and listen, I can use a mic and capture the results and see with my own eyes. Don't try to blame me because you poorly designed your system, that's on you.

Concerning the home front, Yamaha has been working for a while on adding a second smaller coil to the LF driver and using it as a reference voltage (a mic is simply a speaker in reverse) to feed signal comparison against the output and using DSP to modify the output signal, much like current noise-cancelling headphones use.

But outside of that type of technology, you can certainly achieve decent control by properly matching the compliance of the driver to the cabinet design, keeping the load (speaker's VC impedance) of the amp in a region that keeps the DF as far above >100 as possible, keeping leads to the LF driver as short as possible, (preferably only a couple of feet) and 10 gauge or larger, not because of current, but voltage drop. Properly implementing a sub design isn't that hard, no matter the environment. And just because you are placing this in a vehicle, doesn't negate the very same engineering principles used in any other environment. And since Class D doesn't perform to the DF levels of thousands like can be achieved by Class A/B, then attempting to load it @ 2 or 1 ohm can only do you more harm than good on DF. This is just simple design considerations. Get real.


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## GreatLaBroski

DeltaB said:


> Concerning the home front, Yamaha has been working for a while on adding a second smaller coil to the LF driver and using it as a reference voltage (a mic is simply a speaker in reverse) to feed signal comparison against the output and using DSP to modify the output signal, much like current noise-cancelling headphones use.


Any idea if they're using a FxLMS algorithm? I'm considering tinkering with a custom DSP to achieve that in-car and I'm trying to think about how I'd do it.


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## Holmz

DeltaB said:


> ...
> 
> But outside of that type of technology, you can certainly achieve decent control by properly matching the compliance of the driver to the cabinet design, keeping the load (speaker's VC impedance) of the amp in a region that keeps the DF as far above >100 as possible, keeping leads to the LF driver as short as possible, (preferably only a couple of feet) and 10 gauge or larger, not because of current, but voltage drop. Properly implementing a sub design isn't that hard, no matter the environment. And just because you are placing this in a vehicle, doesn't negate the very same engineering principles used in any other environment. And since Class D doesn't perform to the DF levels of thousands like can be achieved by Class A/B, then attempting to load it @ 2 or 1 ohm can only do you more harm than good on DF. This is just simple design considerations. Get real.


How does the low DF manifest itself on the sound compared to a high DF?


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## DeltaB

Holmz said:


> How does the low DF manifest itself on the sound compared to a high DF?


It has already been stated a few times in this thread. Please see previous posts.

Interestingly enough, Greg Timbers, the highly regarded Chief Engineer of JBL fame of speakers like the Everest, as well as almost every famous JBL design, especially studio monitors, since the 70's was asked;

Anechoic or listening? That is, where do measurements and listening fall in design? (Value, importance, role…)

"This is a loaded question. I am going to answer it as I believe is correct. All designs *require and deserve* full Anechoic and other types of measurements. The cost, size or intended market for the device should not change the measurements taken. It doesn't matter how expensive a loudspeaker is, it should always be the absolutely best effort within the constraints agreed upon by cost, performance, appearance, etc. In many respects, cheap speakers are actually more challenging to do correctly. Once you know what your parts are capable of, you can work to achieve the highest level of performance possible within the guidelines."


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## DeltaB

GreatLaBroski said:


> Any idea if they're using a FxLMS algorithm? I'm considering tinkering with a custom DSP to achieve that in-car and I'm trying to think about how I'd do it.


I don't have first hand knowledge of what those boys over in Japan are cooking up, however, the YST technology is currently available in the home sub market.


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## dcfis

That's why jbl is mythical God like status in the recording, venue, 2 channel, and even car with the Gti. 





DeltaB said:


> Holmz said:
> 
> 
> 
> How does the low DF manifest itself on the sound compared to a high DF?
> 
> 
> 
> It has already been stated a few times in this thread. Please see previous posts.
> 
> Interestingly enough, Greg Timbers, the highly regarded Chief Engineer of JBL fame of speakers like the Everest, as well as almost every famous JBL design, especially studio monitors, since the 70's was asked;
> 
> Anechoic or listening? That is, where do measurements and listening fall in design? (Value, importance, role…)
> 
> "This is a loaded question. I am going to answer it as I believe is correct. All designs *require and deserve* full Anechoic and other types of measurements. The cost, size or intended market for the device should not change the measurements taken. It doesn't matter how expensive a loudspeaker is, it should always be the absolutely best effort within the constraints agreed upon by cost, performance, appearance, etc. In many respects, cheap speakers are actually more challenging to do correctly. Once you know what your parts are capable of, you can work to achieve the highest level of performance possible within the guidelines."
Click to expand...


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## GreatLaBroski

DeltaB said:


> I don't have first hand knowledge of what those boys over in Japan are cooking up, however, the YST technology is currently available in the home sub market.


Gotcha, thanks


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## DeltaB

ChrisB said:


> So you are telling me if one can't tell a difference in a listening test, then it doesn't matter? I've seen plenty of high end manufacturers butt-hurt over cheaper amps performing better than their SQriffic examples throughout the years. They even try to rationalize that a listening test isn't long enough to tell a true difference or come up with other ways to invalidate the test.
> 
> But I'll digress, spend the money on what you want to spend your money on. If one thinks that damping factor of 500 is what it takes to achieve SQ, even when there is no industry standard for where said damping factor is measured, then by all means, spend away.
> 
> I'm just saying there are other places to look if something sounds wonky besides damping factor.
> 
> Finally, audio is my hobby and I'm just a nerd with some calibrated measuring equipment and a computerized RTA that allows me to send signal and measure on the same loop so I can apply an equalization curve that sounds good to me, and 99% of everyone else who listens to my system from the driver's seat. But hey, if you think damping factor is where the SQ difference is based on nominal impedance without taking box rise into consideration, be my guest! That's the beauty of the First Amendment and internet forums.


I quoted the much acclaimed and infinitely respected Greg Timbers, the highly regarded Chief Engineer of JBL, and he stated this concerning listening tests as it relates to results on design;

"I have no use for blind and double blind listening tests the way Harman implements them. Sound systems and their environments are very complicated. No speaker is even close to sounding "real" so personal opinion is always a major consideration. Most blind tests are based on a series of assumptions that enable the test to be easy or practical to implement. Unfortunately, these assumptions often invalidate or color the results because they cover up or accentuate aspects of the loudspeaker design."

I certainly don't stand alone in the audio industry when it comes to the BS of trying to introduce A/B listening tests in its subjective results as the criteria of testing results.


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