The science behind why.....

[Gazzip]

..... some amplifiers measure the same as one another but do not actually sound the same as one another.

http://www.audiomisc.co.uk/distortion/page1.html

Just in case you missed it.

 

[ID.]

Interesting, but it seems rather preliminary and none of it is actually tested or measured that well.

Also, there's the question about at what point some of this becomes audible.

I'm not fully in the all amps sound the same camp because I agree that the program material (music or whatever ) and speakers will have an impact, but Im not a fan of completely ignoring measurements because for my tastes ive found equipment that measures well works the best with a wide range of music.

 

[matt49]

The science is probably sound. (Actually I'd be very surprised if it wasn't.) But Lesurf is careful to say he doesn't know whether any of these effects are audible.

 

[Gazzip]

Interesting, but it seems rather preliminary and none of it is actually tested or measured that well.

Also, there's the question about at what point some of this becomes audible.

I'm not fully in the all amps sound the same camp because I agree that the program material (music or whatever ) and speakers will have an impact, but Im not a fan of completely ignoring measurements because for my tastes ive found equipment that measures well works the best with a wide range of music.

I think that the author, who is an eminent physicist incidentally, considers the failings of THD and IMD in measuring audio amplifier performance to be fundamentally flawed in a more than preliminary sense.

His new, proposed measurement method is preliminary yes, but his discrediting of THD and IMD measurements is nothing new and is widely accepted.

Unfortunately it is THD and IMD which are the industry standard used by manufacturers for benchmarking amplifier distortion. Easy to achieve good results, utterly meaningless and yet cited again and again in "proving" that all amplifiers sound the same.

 

[Vladimir]

If I understood well (some of it) his idea is not to measure for distortion with test tones (sine or square waves) because they don't represent music well (bad analog), but to measure real music samples for distortion and see how the amp is tracking the original signal. This idea of course is not new in audio, but his method how to do this is probably unique considering he has written a book about MM waves (millimeter waves, 30-300GHz).

 

[ID.]

I'm all for improvement in how to measure.

Does he have anything to say anywhere about class D amps?