Can you hear a difference in Sound between Audio Amplifiers?

[Swerd]

I believe meaningful results can be achieved in an afternoon for speakers, but not for electronics. Except in rare cases I can't hear any differences between electronics on quick comparisons, but I do sometimes experience differences in listener fatigue, and in some cases that takes much more than an hour. And I like to do it over multiple days to rule out anomalies with my own perception as much as possible.

As the differences in gear's sound become harder to detect, you need test results from more and more people. For example, let's imagine some test results where there are actually positive results. First, you have to subtract the negative control results from the experimental test results:

For speakers, where we expect an easier time:
A vs. B test 70% detect a difference.
A vs. A test 25% detect a difference.
70% – 25% = 45%

But for amps or other electronics, it may be harder:
A vs. B test 65% detect a difference.
A vs. A test 50% detect a difference.
65% – 50% = 15%

Because the speaker test results have a larger signal (45%) and the amp test results have a lower signal (15%), you need to test more people (larger N) before you can say with any confidence that the amp results are real as opposed to guessing. As the control adjusted signal level goes down, the confidence that people are not guessing goes down. Eventually you conclude that a difference isn't possible to distinguish from guessing. I don't see how allowing more time for the test allows greater sensitivity. It allows more possibility of un-blinding the test subjects.

 

[PENG]

That's all good except one drawback for such long terms exercise, mood will become a factor, though that can be mitigated to a large extent, if Swerd's procedures are all followed.

 

[3db]

I didn't answer this poll. I have beaten, flogged, shot, had the same mule reborn just to beat, flog, and shoot it again. Not going there on this thread.

 

[Irvrobinson]

Thanks for sharing. That's special. ;-)

Sent from my SM-G928V using Tapatalk

 

[3db]

Thanks for sharing. That's special. ;-)

Sent from my SM-G928V using Tapatalk

Any time Irv

 

[jinjuku]

Well, I am the anti-audio-DBT troll which ADTG (and perhaps PENG) is referring to. DBTs are the best known way to test the effectiveness of anti-pimple creams, but for audio, well, you can't really appreciate how useless they are for testing ability to discern subtlety until you participate in a few.

I've participated in quite more than a few... It's data gathering Irv. What I don't get myself in a lather over is when my results fall into the category of just guessing.

I recently did this with A/D converters at $200, $1000, $5000. You know what me and 7 other people found out? They make some really good A/D converters for $200.

Out of the 8 of us two were recording engineers.

 

[jinjuku]

Swerd, chill. I despise blind testing for audio not because I think sighted listening tests are any better, but because I think human audio memory is so poor for such subtleties as exist between electronics that any comparison testing without a reference is useless.

With that said. Sighted long term, subjective, statements about night and day differences are by fact even worse.

*I'm not lumping you into that category BTW.

 

[AcuDefTechGuy]

Yeah, I think the Poll should read:

How much of a sound quality difference is there among accurate amplifiers when level matched using the same source?

1. Night-and-Day Difference
2. Subtle Difference
3. Absolutely No Difference

 

[auronihilist99]

Objectivists - Unsighted, volume level-matched listening evaluations has proven that audible differences between SS amps are non-existent.

Subjectivists - Sighted, volume level-matched listening evaluations has proven that subtle audible differences between SS amps do exist.

 

[Irvrobinson]

With that said. Sighted long term, subjective, statements about night and day differences are by fact even worse.

*I'm not lumping you into that category BTW.

I know. I'm just of a mind that electronics will always fall into a measurements + personal opinion decision process, and blinded tests or subjective fantasy reviews are just a waste of time (as they basically have always been).

 

[jinjuku]

Awesome, but complicated and possibly expensive to implement.

One flaw: You have a 50/50 opportunity and

I know. I'm just of a mind that electronics will always fall into a measurements + personal opinion decision process, and blinded tests or subjective fantasy reviews are just a waste of time (as they basically have always been).

When we did the SBT of A/D converters it wasn't a waste of time. It was informative.

 

[Steve81]

One flaw: You have a 50/50 opportunity

Again, depends on the test design. The choice doesn't have to be binary; a third option can/should exist in this test, i.e. that a listener couldn't discern a difference between A and B.

 

[AcuDefTechGuy]

Subjectivists - Sighted, volume level-matched listening evaluations has proven that subtle audible differences between SS amps do exist.

I would definitely give them that "subtle difference".

It's like pennies in your pocket. Not worth arguing over.

 

[auronihilist99]

It's like pocket change. Not worth arguing over.

Or spending an extra $2000.00 over.

 

[Steve81]

When we did the SBT of A/D converters it wasn't a waste of time. It was informative.

It's informative, but the question is can you inform your biases away? I'm no expert in the field of psychology, but even hardened objectivists like Arnold Kreuger suggest that you can't.

What happens is that you hear the same false differences as ever if you should use old fashioned listening unscientific test procedures, only you now know that they are likely false....IME intellectual knowledge about something does not change how you perceive it, it changes how you respond to it. I like sweets and even though I know that eating too many sweets can be bad for me, I still like sweets as much as ever.

 

[Steve81]

How much of a sound quality difference is there among amplifiers when level matched using the same source?

1. Night-and-Day Difference
2. Subtle Difference
3. Absolutely No Difference

Don't forget Peter Aczel's qualifiers:

If amplifiers A and B both have flat frequency response, low noise floor, reasonably low distortion, high input impedance, low output impedance, and are not clipped, they will be indistinguishable in sound at matched levels no matter what’s inside them.

and this part...

Of course, some of the new “alphabet soup” topologies do not necessarily satisfy those conditions.

And of course some amps are just plain crap...

After my distortion measurements, I decided not to listen to the SLC-A300. Harmonic distortion from 0.5% up to 3.5% is unquestionably audible, and then I’d be knee-deep in the fruitless argument about the alleged superiority of the Soaring Audio’s processed sound to the unprocessed sound of a neutral amplifier. Forget about it; I won’t go there.

Or this monstrosity that Stereophile reviewed/measured:

What is subjectively important is the SH-833's behavior in the bass. As with another amplifier using a circuit developed by the late Shishido-san—the Antique Sound Lab Explorer reviewed by Art Dudley in March 2004—there is a bass boost, the amount of which depends on the output transformer tap, the source impedance, and the load impedance. In the worst case, 4 ohm tap into 16 ohms, the boost reaches 9dB between 80Hz and 160Hz, while in the best case, 8 ohm tap into 2 ohms, there is a broad plateau 2dB high between 30Hz and 200Hz. With our simulated loudspeaker load, the high source impedance and exaggerated low frequencies produce a well-defined, 10dB peak at the woofer's resonant frequency.

 

[AcuDefTechGuy]

Or spending an extra $2000.00 over.

Well, monetary value/worth is equivocal for sure.

I won't argue that aesthetic, resale value, and pride of ownership are not worth an extra $2,000. If it makes you happy (even therapeutic), it can't be that bad, right?

 

[AcuDefTechGuy]

Don't forget Peter Aczel's qualifiers:



and this part...


And of course some amps are just plain crap...


Or this monstrosity that Stereophile reviewed/measured:

Okay, I edited "Accurate Amplifiers".

 

[Steve81]

Okay, I edited "Accurate Amplifiers".

But there's the rub: what's accurate under one set of circumstances (FR into an 8 ohm resistor, driving 1kHz sine waves into said resistor) may not be accurate under another set of conditions (driving my speakers with real content at the volumes I desire). This isn't to imply that one needs megabuck amplification, but things are more complicated than a blanket statement.

 

[jinjuku]

It's informative, but the question is can you inform your biases away? I'm no expert in the field of psychology, but even hardened objectivists like Arnold Kreuger suggest that you can't.

You may not. But since I had no knowledge of what A/D was what it didn't matter.

For me what happened years ago is that I went through Carver, Adcom, Parasound, Accuphase.

I picked up a Crown XLS 402D for $179 on a lark and was floored by performance for $179. That and it had a lower noise floor than the Parasounds I had at the time.

It took me all of three days to jettison the Adcom and Parasounds.

I take Arny's point but honestly don't feel it applied to me. So I take that with a grain of salt.