Can you hear a difference in Sound between Audio Amplifiers?

[jsrtheta]

Not to me it isn't. If my guests all reliably tell me that config 1 is drier and brighter than config 2 (for example) but don't know that's what I'm hearing too, then as far as I'm concerned it validates what I'm hearing.



Or maybe not, because I don't disagree with him.

Unless of course his definition of 'transparent' is perfection.

"It validates what I'm hearing." That is incredibly unscientific and wrong. That is precisely why double-blind testing is the only way to have any semblance of certainty.

 

[Art Vandelay]

"It validates what I'm hearing." That is incredibly unscientific and wrong. That is precisely why double-blind testing is the only way to have any semblance of certainty.

So tell me why or how a DBT would give a different result? In my example the amplifier under test is being compared against itself, so looks count for nought. Granted that there is some decrease in certainty from the slight delay in switching between configs, but at least the it's guaranteed that frequency response and amplitude are absolutely the same, which can't be guaranteed when 2 different amplifiers are being compared.

 

[jsrtheta]

If you are in the process of tweaking your own design piece, or for a company, then of course you could vary the sound to your liking by such tweaking, at some point during the process. Even then, in such cases, what is "just right" for you may not be right for others so if you were to sell it to the market you would want to tweak it, measure it, and finalize your tweak according to the measurements. If not, then that product won't be for people who would rather trust verifiable specs, not your personal preference.

With due respect, I must also say that if it is something that simple, manufacturers would have figured that out and done it already. I think you can only convince the objective group by passing at least some properly conducted blind comparison tests, that there is audible difference between say for example, a Byrston 4B SST, 4BSST3, McIntosh MC452, ATI1802, 8002, Halo A21, Monolith 2X200W, Emotiva XPA-2, UPA-200 and my old Denon AVR-3805, or my very old Marantz SM-7, when all used well below their clipping point even during peaks of the test sample music. The key is "used well below.....", not just "all amps sound them same.." because we already know that they don't.

"We already know they don't." Huh?

 

[jsrtheta]

So tell me why or how a DBT would give a different result? In my example the amplifier under test is being compared against itself, so looks count for nought. Granted that there is some decrease in certainty from the slight delay in switching between configs, but at least the it's guaranteed that frequency response and amplitude are absolutely the same, which can't be guaranteed when 2 different amplifiers are being compared.

First, the "slight delay" means your memory of a particular "configuration" cannot be trusted. Hell, if your head is not in the same listening position within a couple of inches, you will hear a difference.

Secondly, you are changing things, no? Otherwise, what are you comparing to what? Obviously, not the amplifier, but, in your case, "configurations," which you are trying to compare to each other in order to determine differences. So the "amplifier" argument is a red herring, because you are not changing the amplifier but you are changing something in the signal path and you are looking for differences.

And if DBT has proven one thing, it is that when the "blindfolds" come out, certainty and accuracy go out the window. At that point, any difference heard may be significant, but not because the listener knows what he's listening to. Usually, when testing anything other than speakers, though by no means always, no difference can be reliably detected (and it takes a number of tests to establish this - if you make the change, and then do only one test, any result is meaningless).

"Audiophiles" have this aversion to scientific testing because it might upset their belief system. That is not the way science works. It's the way cults work.

 

[PENG]

"We already know they don't." Huh?

If you don't specify the conditions under test, you have to know that they aren't going to sound the same under certain different conditions, don't you?

 

[jsrtheta]

If you don't specify the conditions under test, you have to know that they aren't going to sound the same under different conditions, don't you?

Sorry - might have missed something on first read.

 

[PENG]

Sorry - might have missed something on first read.

No problem, to be clearer, I meant, say if we compare a 80 W 8 ohm 100 W 4 ohm AVR to a 200 W 8 ohm, 300 W 4 ohm amp driving a pair of B&W 800 diamond speakers to produce 85 dB average spl in a 15X25X10' room, they are going to sound different. So how can we say "ALL" amp sounds the same.... or amps don't sound different?

 

[AcuDefTechGuy]

No problem, to be clearer, I meant, say if we compare a 80 W 8 ohm 100 W 4 ohm AVR to a 200 W 8 ohm, 300 W 4 ohm amp driving a pair of B&W 800 diamond speakers to produce 85 dB average spl in a 15X25X10' room, they are going to sound different. So how can we say "ALL" amp sounds the same.... or amps don't sound different?

Depends on how far you listen, 10FT or 20FT.

If it’s not a blind test, it depends on your mood.

 

[mtrycrafts]

No problem, to be clearer, I meant, say if we compare a 80 W 8 ohm 100 W 4 ohm AVR to a 200 W 8 ohm, 300 W 4 ohm amp driving a pair of B&W 800 diamond speakers to produce 85 dB average spl in a 15X25X10' room, they are going to sound different. So how can we say "ALL" amp sounds the same.... or amps don't sound different?

Well, if the test produces differences under those conditions and under level matched DBT, then the weaker amp is driven beyond its capability in that test. Of course one amp was driven beyond it capability and the test, for all practical purposes is invalid. Hence, one of the premised condition was exceeded.

ps. remember the Steve Zipser amp comparison many moons ago with Nousaine being present,
a $300 Yam integrated could not be differentiated with a Aleph 1. something monoblock costing $10k+++

 

[Art Vandelay]

First, the "slight delay" means your memory of a particular "configuration" cannot be trusted. Hell, if your head is not in the same listening position within a couple of inches, you will hear a difference.

Same problems potentially corrupt DBT results too, no?

Secondly, you are changing things, no? Otherwise, what are you comparing to what? Obviously, not the amplifier, but, in your case, "configurations," which you are trying to compare to each other in order to determine differences. So the "amplifier" argument is a red herring, because you are not changing the amplifier but you are changing something in the signal path and you are looking for differences.

There is always a reference configuration in any listening test I've set up, and I don't necessarily tell the listeners which configuration they're listening to, other than a label of A, B, or C. If I was to tell them which design configuration was used it could result in a bias due to a preconception.

And if DBT has proven one thing, it is that when the "blindfolds" come out, certainty and accuracy go out the window. At that point, any difference heard may be significant, but not because the listener knows what he's listening to. Usually, when testing anything other than speakers, though by no means always, no difference can be reliably detected (and it takes a number of tests to establish this - if you make the change, and then do only one test, any result is meaningless).

The point of DBT is to remove bias due to a preconception that brand A is better than brand B, or expensive is better than cheap etc. Obviously if you're comparing a component against something that looks exactly the same a bias cannot exist.

"Audiophiles" have this aversion to scientific testing because it might upset their belief system. That is not the way science works. It's the way cults work.

I can't really agree with this statement because it seeks to stereotype a group of people that is actually quite diverse and includes individuals with a wide range of science and engineering knowledge. It's worth pointing out that many highly qualified audio engineers are also audiophiles and some of these people also design amplifiers in specific ways that often defy the accepted engineering metrics.

It's worth reminding ourselves occasionally; To be scientific is to be inquisitive and open minded.

 

[Art Vandelay]

No problem, to be clearer, I meant, say if we compare a 80 W 8 ohm 100 W 4 ohm AVR to a 200 W 8 ohm, 300 W 4 ohm amp driving a pair of B&W 800 diamond speakers to produce 85 dB average spl in a 15X25X10' room, they are going to sound different. So how can we say "ALL" amp sounds the same.... or amps don't sound different?

They may or may not sound the same (or similar), because those basic specifications don't really tell us much about the performance of an amplifier, even if the load impedance is known.

 

[PENG]

They may or may not sound the same (or similar), because those basic specifications don't really tell us much about the performance of an amplifier, even if the load impedance is known.

If you read and understood my post, you would not be saying this. I used a specific example of an 80W/100W AVR versus a 200/300W 8/4 ohm rated amplifier using 800 diamond speaker to listen at 85 dB spl in a large room, the only thing I omit is stating the listening distance. So let me make it more explicit, say distance is 4 meter, that should be reasonable in a 15' wide 25' long room. That little 80W/100W 8/4 ohm rated AVR is going to clip quite often during movie/music peaks, don't you think, to the point that it would be audible? If not enough, say that AVR is rated only 50W/60W 8/4 ohm and listening distance is 15 ft. Note that I used 800 diamond deliberately to make an extreme case, their impedance dips down close to 3 ohms.

At least I mtrycraft agrees with me, that's good enough for me to make my case.

 

[Johnny2Bad]

...{snip} ...
"Audiophiles" have this aversion to scientific testing because it might upset their belief system. That is not the way science works. It's the way cults work.

Ignoring for the moment that an "Audiophile" is simply someone who enjoys listening to music as a pastime in itself, versus someone who likes to have the Bose radio play while they do the dishes, so to be a member of this forum in the first place makes you an "Audiophile"... *

Audiophiles do not have an aversion to measurement. The entire history of measurement techniques is a story of developing tests to correlate with what listeners hear, and for what the previous tests could not reveal. Without subjective listening, we would have no agreed upon test and measurement standards whatsoever.

Where the Belief Systems of objectivists and subjectivists clash is when the objectivist presents a set of measurements and says "this perfectly describes the performance of the Device Under Test (DUT)" and the subjectivist answers "then why am I still hearing differences that your measurements do not explain?"

At which point a truly objective objectivist will reply, "then lets see if we can devise a new test regimen that explains what you claim to hear" (and that is exactly what has been done, over the 120 or so years of stored music reproduction) while those whose objectivist Belief System is closed (that is, not open to discovery) will say, "no, that's it, if you hear something you must be imagining it as our measurement regimen is perfect and needs no further refinement".

It is the former, and not the latter, that has led us to 2017 where we enjoy the best quality sound reproduction in history. Measurement of amplifiers has not changed in any significant way in 40 years yet today's products sound better than those of 1977. How, do you suppose, that came to be if it were not via listening tests and circuit refinement by Engineers who do value subjective as well as objective metrics, despite those circuits measuring essentially identically over four decades?

If we were to leave it up to the closed minded objectivist, we'd still be using the same circuits found in a 70's era Pioneer receiver. Yet we are not doing so (thankfully)*.

If you were to dust off a CD player from 2005 and popped in a disk, I doubt you would need a DBT to discern that it sounds inferior to the same 16/44.1 file played from a computer and standalone DAC, although you certainly could verify it by doing so.

Yet, in 2004, audiences were awed at the sound of CD, almost without exception the majority of listeners proclaimed it the best possible sound quality possible, period; one that could not possibly be improved upon. Yet we have improved on "perfection". How is this even possible without subjective listening and objective measurement working together to perfect the art?

* If you want some real fun, tell a young woman today that she is a "feminist" or a "hippie" there's a good chance she will become offended, despite the fact that her beliefs are EXACTLY the same as those first advocated by the feminists and hippies of yore.

** Not to malign the Pioneer receiver of yore, especially the "statement" products everyone had in the catalog, they have their qualities, not the least of which is value for money when bought used today, but if you were to listen to a modern day amplifier with the same robust power supply and build quality, forgetting for a moment that you probably would have to pay $5,000 or more for it, it would almost certainly sound better.

 

[jsrtheta]

No problem, to be clearer, I meant, say if we compare a 80 W 8 ohm 100 W 4 ohm AVR to a 200 W 8 ohm, 300 W 4 ohm amp driving a pair of B&W 800 diamond speakers to produce 85 dB average spl in a 15X25X10' room, they are going to sound different. So how can we say "ALL" amp sounds the same.... or amps don't sound different?

I don't know that to be true at all.

 

[PENG]

Depends on how far you listen, 10FT or 20FT.

If it’s not a blind test, it depends on your mood.

You should know by now I meant 20 ft because you could see how desperate I was to make my point that amps could sound different under certain different test conditions, i.e. one is over stressed while the other is not.

 

[jsrtheta]

Ignoring for the moment that an "Audiophile" is simply someone who enjoys listening to music as a pastime in itself, versus someone who likes to have the Bose radio play while they do the dishes, so to be a member of this forum in the first place makes you an "Audiophile"... *

- No, you are describing a music lover, not an audiophile. One can be both, of course, but they are not synonyms.

Audiophiles do not have an aversion to measurement. The entire history of measurement techniques is a story of developing tests to correlate with what listeners hear, and for what the previous tests could not reveal. Without subjective listening, we would have no agreed upon test and measurement standards whatsoever.

- What "history"? We are talking the science of sound. Many disciplines go into it, and I am not aware of any "history" of perplexed audio fans desperately trying to discover this science so they can measure it.

- Because you have a number of psychological, and acoustical, factors you are not even acknowledging. Until you do, you will not be informed on this subject. It's rather like the patient who takes a
homeopathic remedy and starts to feel better, even though it's only placebo effect. Billions are spent by fools who would know better if they cared to learn. Instead, they buy the hogwash that a substance diluted in water to the point there are no molecules of the substance left is still effective because the water "remembers" the molecules. I know audiophiles who laugh at the suckers, then claim that, a la Synergistic Research, that cables improve in sound quality as the electrons "learn" the best path through them.


At which point a truly objective objectivist will reply, "then lets see if we can devise a new test regimen that explains what you claim to hear" (and that is exactly what has been done, over the 120 or so years of stored music reproduction) while those whose objectivist Belief System is closed (that is, not open to discovery) will say, "no, that's it, if you hear something you must be imagining it as our measurement regimen is perfect and needs no further refinement".

- You keep saying this. Your source for this?

It is the former, and not the latter, that has led us to 2017 where we enjoy the best quality sound reproduction in history. Measurement of amplifiers has not changed in any significant way in 40 years yet today's products sound better than those of 1977. How, do you suppose, that came to be if it were not via listening tests and circuit refinement by Engineers who do value subjective as well as objective metrics, despite those circuits measuring essentially identically over four decades?

If we were to leave it up to the closed minded objectivist, we'd still be using the same circuits found in a 70's era Pioneer receiver. Yet we are not doing so (thankfully)*.

- No, you wouldn't, because you misunderstand the fundamental of scientific progress. And human nature. Look how many pointless "advances" have been made in digital conversion that are for all intents inaudible. There is, maybe unfortunately, no shortage of audio designers who believe they can make a better mousetrap.

If you were to dust off a CD player from 2005 and popped in a disk, I doubt you would need a DBT to discern that it sounds inferior to the same 16/44.1 file played from a computer and standalone DAC, although you certainly could verify it by doing so.

- How would that possibly be so? Are the ones more "oneish" and the zeros more "zeroish"? And I note how quickly you dispose of the need for DBT. Without DBT, you cannot support your claim. Is that why you resist it?

Yet, in 2004, audiences were awed at the sound of CD, almost without exception the majority of listeners proclaimed it the best possible sound quality possible, period; one that could not possibly be improved upon. Yet we have improved on "perfection". How is this even possible without subjective listening and objective measurement working together to perfect the art?

- How have we improved upon "perfection"? Where are your DBTs showing listeners can reliably differentiate between 16/44 and 24/192?

* If you want some real fun, tell a young woman today that she is a "feminist"; there's a good chance she will become offended, despite the fact that her beliefs are EXACTLY the same as the feminists of yore.

- Actually, no there isn't such a "good chance." And your quip is offensive.

 

[jsrtheta]

You should know by now I meant 20 ft because you could see how desperate I was to make my point that amps could sound different under certain different test conditions, i.e. one is over stressed while the other is not.

Well, you didn't say that. And if you played all of these amps within the range of volume the lowest rated amp can comfortably handle, they might not sound different at all.

 

[M Code]

Measurement of amplifiers has not changed in any significant way in 40 years yet today's products sound better than those of 1977. How, do you suppose, that came to be if it were not via listening tests and circuit refinement by Engineers who do value subjective as well as objective metrics, despite those circuits measuring essentially identically over four decades?

Hmmm....
Have to debate this point in the last 25 years there have been tremendous strides in amplifier measurements... In the old days we used the HP 221C then moved up to the Sound Technology 1700 but the entire landscape changed when Audio Precision entered.. The problem with the early measuring stuff was that their residual THD was often higher than the component being measured... Then the Cascade 2 & 586 became available so we can now measure components down to 0.0001%..

But as pappy always said "It if measures good, but sounds bad, it is bad.."

Just my $0.02..

 

[3db]

You should know by now I meant 20 ft because you could see how desperate I was to make my point that amps could sound different under certain different test conditions, i.e. one is over stressed while the other is not.

I have always qualified my answers with this vague question. You are also providing qualifications. I find it amusing that the nay sayers who think amps sound differently dont have any qualifications to support their answers.

 

[mtrycrafts]

...I find it amusing that the nay sayers who think amps sound differently dont have any qualifications to support their answers.

Why would they? To them, it sounds different under all sighted conditions.
And, they don't accept DBT so they exclude that as a given.