Can you hear a difference in Sound between Audio Amplifiers?

[RichB]

And why would you do that?The power is cut way down or limited.

Listen at a view level well below the where clipping and limitting is expected. It's a simple experiment for those who want to hear and recognize limiting.

Of coarse, remember to reset it it 8 ohms

- Rich

 

[lovinthehd]

I hooked up a 100 Yamaha.
- Rich

That's a model number?

 

[RichB]

That's a model number?

Aventage RX-A820.

- Rich

 

[Swerd]

51% of the folks who voted on this thread have heard the difference between amps. So, I am sit comfortably among the unwashed masses.

I'll always defend your rights to voice your opinions. But that doesn't prevent me from saying they are unwashed opinions and not the results of valid listening tests. I doubt any of those who voted on this survey did a blind listening test, even if only one person was involved. Therefore, what they claimed they heard has of little, if any, value.

Unless there are blind listening test results where enough people have been tested to achieve statistical significance (at least 40-50 people), no one can say anything at all useful about the audible effects of amplifiers on speakers.

Any attempt to argue against blind listening tests as a valid method is no more than an empty hand-waving effort to discredit or ignore the only method actually known to work.

 

[lovinthehd]

Aventage RX-A820.

- Rich

I was thinking more like what a search got me https://www.google.com/#q=100+yamaha

 

[PENG]

51% of the folks who voted on this thread have heard the difference between amps. So, I am sit comfortably among the unwashed masses.

Even with a properly empanelled trained listeners, you can have either finding distinguishable or not and yet, you would only prove that those listeners with that system in that room on that day found X. An amp may be indistinguishable driving one set of speakers may not be with another.

This is a good interview with Jon Iverson discussion blind testing and the nature of audio testing. Harman tests with trained listeners. Otherwise, you are testing the listeners and not the equipment.

https://twit.tv/shows/home-theater-geeks/episodes/221

- Rich

Very interesting interview, safe to say they did not find the so called "night and day" kind of difference in their experiment.

 

[RichB]

Any attempt to argue against blind listening tests as a valid method is no more than an empty hand-waving effort to discredit or ignore the only method actually known to work.

I am not arguing against blind testing but I find Iverson's observations interesting and sensible. It seems obvious that a given test validity is limited by the test procedure, equipment, and listener skill. Harman uses trained listeners and as you can see, I am a big fan of the results

Since we cannot perform blind testing for all our gear, we read reviews and sometimes seek the opinions about the sound quality and experiences with specific gear.

Personally, I shy away from telling people what to buy, but I will express my thoughts on the purchases that I have made. Apparently, that is controversial

I do encourage those so inclined to try things at home, especially, when it costs little or nothing to do so.

- Rich

 

[RichB]

Very interesting interview, safe to say they did not find the so called "night and day" kind of difference in their experiment.

Yes, and that makes it all the more believable

- Rich

 

[herbu]

no one can say anything at all useful about the audible effects of amplifiers on speakers.

But if all the useless information was removed from forums, they would all certainly die.

Separating the useful from the useless is part of the fun. And more especially, watching others attempt to do it is quite entertaining to me.

 

[Swerd]

These two quotes from your earlier posts demonstrate what I object to.

I hooked up a 100 Yamaha to my Salon2's. This was not a good match.
I could not find the Yamaha display showing the clipping and distortion levels.

If you want to hear the effect of limited power on an AVR, switch it into 4 ohm mode. I'll bet you can tell the difference at surprisingly low listening levels.

Your first one says, under certain conditions, you can can easily hear differences. You mention no efforts to deal with built-in listener or test biases. I wonder if any controls at all were done. Yet you state your conclusions with total confidence.

Even with a properly empanelled trained listeners, you can have either finding distinguishable or not and yet, you would only prove that those listeners with that system in that room on that day found X. An amp may be indistinguishable driving one set of speakers may not be with another.

Your second quote talks about some of the difficulties faced by any listening test whether its done blind or sighted. The people at Harmon understand that any listening test is only as good as the controls they build into it. They are among the few in the audio industry who take this seriously.

So which is it? Blind confidence with no controls, or blind testing, with all its warnings and caveats? You will never convince people like me by arguing for both.

 

[RichB]

These two quotes from your earlier posts demonstrate what I object to.
Your first one says, under certain conditions, you can can easily hear differences. You mention no efforts to deal with built-in listener or test biases. I wonder if any controls at all were done. Yet you state your conclusions with total confidence.

Usually, I level match with a volt meter. I have done that when comparing listening to the AT6002 and A21. In the case of the Yamaha receiver driving Salon2s was done for a fun. Just a quick listening session at multiple volume levels.

Your second quote talks about some of the difficulties faced by any listening test whether its done blind or sighted. The people at Harmon understand that any listening test is only as good as the controls they build into it. They are among the few in the audio industry who take this seriously.

So which is it? Blind confidence with no controls, or blind testing, with all its warnings and caveats? You will never convince people like me by arguing for both.

I think the problem here is the objective. This thread is "Can you hear a difference in Sound between Audio Amplifiers?". So, this where you state opinions. This is not the thread that proves anything.

Died in the wool objectivists, often listen to systems and go on forums and state they could hear no difference between amp A and AVR B; Proudly stating this observation. This is a valid opinion, but nothing has been proved. Such posters are listening to their systems and stating these opinions, inferring that these are facts. It is a fact that these are opinions.

Concerning blind testing, Harman does it well. Others not so much. I have read posts showing DBT examples where a couple of books-shelf speakers were used with 8 listeners, in an untreated room. No, I don't believe that achieves much.

I do believe that people can listen to their systems and make qualitative judgements. In fact, all of us do. Some measure, some run REQ a dozen times and pick the one that pleases them. Some measure, some don't and there is nothing wrong with that. I measure.

Earlier in this thread, I suggested that those the 4 ohm / current-limiting AVRs may want to try switching that setting and listen to what it sounds like. Call it training in what power-based compression sounds like. It is a simple cost-free experiment. I enjoy doing those types of experiments. I am at a loss at to why that is considered controversial.

- Rich

 

[Swerd]

I think the problem here is the objective. This thread is "Can you hear a difference in Sound between Audio Amplifiers?". So, this where you state opinions. This is not the thread that proves anything.

You and I differ on this point. The thread title does open the floor to discussion, but I don't think it implies 'this is where you state your opinions'.

People do simple things at home to satisfy themselves about choices they make in an audio system without worrying about scientific rigor. I do it all the time. If I talk about it online, I always make an effort to mention that it is my opinion or experience, and not something that has been further confirmed by blind listening tests.

If you say something similar, I'll be happy with that.

It is very important to me when people make claims online that they distinguish between simple comparisons and what they actually can back up with scientific logic and rigor.

 

[PENG]

Died in the wool objectivists, often listen to systems and go on forums and state they could hear no difference between amp A and AVR B; Proudly stating this observation. This is a valid opinion, but nothing has been proved. Such posters are listening to their systems and stating these opinions, inferring that these are facts. It is a fact that these are opinions.

Agree, but it seems that more often than not, it was someone who claimed hearing obvious difference that they suggested others to add an amp, or even a specific amp (recent example: "get a rotel..." etc.). That would then be followed by someone from the "other camp" reacting by countering such claims based on their own experience, or as you said, "opinion". It also seems that on occasions, people from both "camps" would even end up trading insults (I am exaggerating), but most of the time it was in fact started by the "yes, the difference is easy to hear, even night and day" camp. Not that it matters but I think it is fair to point out most of time the yes camp tended to get more defensive and forgot people were really expressing their opinions based on their own experiences, just that often enough they used words that made it like they were stating facts.

Earlier in this thread, I suggested that those the 4 ohm / current-limiting AVRs may want to try switching that setting and listen to what it sounds like. Call it training in what power-based compression sounds like. It is a simple cost-free experiment. I enjoy doing those types of experiments. I am at a loss at to why that is considered controversial.
- Rich

Also agree except the part that you seemed to suggest the difference would be obvious even at low level listening, to me that would defy science. It could also be a matter of how we define "low level". After watching the linked video again, I have to say I am really impressed with the demonstrated objectivity throughout the interview, by both Mr. Wilkinson and Mr. Iverson. I actually took some notes this time:

- In one test, Mr. Iverson scored 6 out of 7, that, to me is enough to say he heard the difference, but it was a subtle difference that he was able to detect, 85% of the time +/-.

- He seemed to imply most people would score 50/50 in such controlled blind tests while there could be 1 in 20 that could score high, hence considered golden ear. Again, he didn't really say that, it is just my own interpretation of what he seemed to be alluding to.

- Even if just one person detected a difference consistently, i.e. such as 6 times out of 7, would prove that there was a difference heard in terms of a "matter of degree".

- He didn't think one could conclude anything from such tests than just confirming a group of people in a specific situation (room, equipment, recordings, the specific series of tests conducted etc..) could detect a difference or not. As he said, really testing the audience, not so much the amps.

- Differences detected wouldn't mean one is better or worse, though it could mean the person prefers one over the other and therefore would conclude that one is "better", but "better" does not equal "more accurate".

- The word "subjective" was used over and over again during the interview, so they both recognized that even though you can conclude there are audible differences that some/trained audience could detect, one could not draw conclusions that one amp sounds more accurate than another.

There was nothing I heard in the interview that contradicted what I believe, that in a properly controlled blind tests, amps designed for accuracy when used within their limits would not sound audibly different, but there could be subtle differences that certain trained people could detect. The fact is, we all know even two same model $3,000 First watt amps will not perform identically all the time, so they should theoretically sound different, it is only a matter of whether the difference can be detected by everyone, or only by someone, trained or not..

Regardless, I would have still enjoyed that video as I find it informative and highly objective in their presentation.

 

[RichB]

Agree, but it seems that more often than not, it was someone who claimed hearing obvious difference that they suggested others to add an amp, or even a specific amp (recent example: "get a rotel..." etc.). That would then be followed by someone from the "other camp" reacting by countering such claims based on their own experience, or as you said, "opinion". It also seems that on occasions, people from both "camps" would even end up trading insults (I am exaggerating), but most of the time it was in fact started by the "yes, the difference is easy to hear, even night and day" camp. Not that it matters but I think it is fair to point out most of time the yes camp tended to get more defensive and forgot people were really expressing their opinions based on their own experiences, just that often enough they used words that made it like they were stating facts.



Also agree except the part that you seemed to suggest the difference would be obvious even at low level listening, to me that would defy science. It could also be a matter of how we define "low level". After watching the linked video again, I have to say I am really impressed with the demonstrated objectivity throughout the interview, by both Mr. Wilkinson and Mr. Iverson. I actually took some notes this time:

- In one test, Mr. Iverson scored 6 out of 7, that, to me is enough to say he heard the difference, but it was a subtle difference that he was able to detect, 85% of the time +/-.

- He seemed to imply most people would score 50/50 in such controlled blind tests while there could be 1 in 20 that could score high, hence considered golden ear. Again, he didn't really say that, it is just my own interpretation of what he seemed to be alluding to.

- Even if just one person detected a difference consistently, i.e. such as 6 times out of 7, would prove that there was a difference heard in terms of a "matter of degree".

- He didn't think one could conclude anything from such tests than just confirming a group of people in a specific situation (room, equipment, recordings, the specific series of tests conducted etc..) could detect a difference or not. As he said, really testing the audience, not so much the amps.

- Differences detected wouldn't mean one is better or worse, though it could mean the person prefers one over the other and therefore would conclude that one is "better", but "better" does not equal "more accurate".

- The word "subjective" was used over and over again during the interview, so they both recognized that even though you can conclude there are audible differences that some/trained audience could detect, one could not draw conclusions that one amp sounds more accurate than another.

There was nothing I heard in the interview that contradicted what I believe, that in a properly controlled blind tests, amps designed for accuracy when used within their limits would not sound audibly different, but there could be subtle differences that certain trained people could detect. The fact is, we all know even two same model $3,000 First watt amps will not perform identically all the time, so they should theoretically sound different, it is only a matter of whether the difference can be detected by everyone, or only by someone, trained or not..

Regardless, I would have still enjoyed that video as I find it informative and highly objective in their presentation.

Good recap. I had the same reaction. There interview presents conservative and measured view of blind-testing which, in my view, was not "against" DBT's.

- Rich

 

[Swerd]

Good recap. I had the same reaction. There interview presents conservative and measured view of blind-testing which, in my view, was not "against" DBT's.

Agreed. That's the state-of-the-art in listening tests, or any other tests of human perception. I wish it were better, but it is what it is.

 

[PENG]

Good recap. I had the same reaction. There interview presents conservative and measured view of blind-testing which, in my view, was not "against" DBT's.

- Rich

FYI, I had a couple of important typo that I have fixed since, but that's after you quoted part of my post so the errors remained in the quoted part in your post#894.

 

[RichB]

FYI, I had a couple of important typo that I have fixed since, but that's after you quoted part of my post so the errors remained in the quoted part in your post#894.

My post quote has been edited to reflect these changes.

- Rich

 

[mtrycrafts]

...
- In one test, Mr. Iverson scored 6 out of 7, that, to me is enough to say he heard the difference, but it was a subtle difference that he was able to detect, 85% of the time +/-.
...

- Even if just one person detected a difference consistently, i.e. such as 6 times out of 7, would prove that there was a difference heard in terms of a "matter of degree"...

I'd just like to comment on those two points from that link you posted. 7 trials is really insufficient to make that conclusion on that persons's part. Now, if it was 9 of 10 trial, then we we could say, hey lets try it again with 15 or 20 trials and see how well it comes out. A minimum of 10 trials is needed from what I have been reading over the years.

 

[Swerd]

I'd just like to comment on those two points from that link you posted. 7 trials is really insufficient to make that conclusion on that persons's part…

Where I work there are some real bona fide statisticians who earn a good living telling the rest of us doing cancer clinical trials how to get statistics right with the fewest number of patients. They really understand how to design blind trials so the answers mean something.

Once I was talking to one of them about, of all things, audio, a subject he liked. So I asked him his take on how many trials and how many test subjects would he like to see in a statistically valid blind listening test.

He didn't know a good answer for how many repeated tests one individual should do. He hoped 12 repeats would be enough. But he was very clear about how many individuals are needed. If the likelihood of just guessing is 50/50, it will require about 50 individuals in the test. The test subjects should have enough opportunity to hear an A/B test (where the answer might be 'yes, I hear a difference') as well as an A/A or B/B test (where the answer should be 'no I cannot hear a difference').

And the conclusions from a test with 50 people (N=50) are only a simple yes or no. To have a statistically valid estimate of how many people might actually hear differences would require 300 to 500 people (N=300-500)!

Now you know why I roll my eyes when one person (N=1) claims to hear differences.

 

[RichB]

Now you know why I roll my eyes when one person (N=1) claims to hear differences.

"Can you and 49 associates reliably hear a difference in Sound between Audio Amplifiers in a Double-Blind Test with at least 10 tries per person?"

- Rich