http://www.geocities.com/altbinariessoundsmusicclassical/mp3test.html
Many thanks for the article. I read it with interest. I have few comments.
First of all, on the basis of presented data, the conclusion in “Summing up” is wrong. It says “But when deciding between 256 kbps encoded MP3s and the original CD, no difference could be determined, on average, for all the pieces.” This is false. The only conclusion the actual data support (accepting the score system that they used) is that the listeners, on average, couldn’t tell whether it was 256 kbps MP3 or original CD. You cannot draw the conclusion that the listeners didn’t hear any difference at all. They couldn’t tell which one was which, which is not the same as not hearing differences at all.
This is exactly what I said before. Often I cannot tell which 320 kbps MP3 is and which the original is. But often I can tell that one sounds differently from the other. Then whether you perceive the former or the latter as better is a matter of personal preferences. For me, and by definition, anything that sounds differently from the original is worse. The truth, the whole truth, and nothing but the truth, so help me God! The truth in this context is what artists, musicians, and producers approved in studio to be released.
Actually, MP3 may be perceived as more pleasant than the original. MP3 removes some noise and some of harmonic complexity which can make the music to sound clearer and easier both to reproduce and listen to. For me, it is the hearing all the details of all that complexity that makes me happy.
Therefore, the question posed in the article is the wrong one. The right question is “Do you hear a difference between A and B?” You present only 2 alternatives to the listener (MP3 and original), and you don’t tell him whether you play A 2 times, B 2 times, or A and B – you select this randomly and relate listeners answers to this. Given a number of tracks and listeners, you may then statistically answer the question whether 320 kbps is audibly different from original.
But this is not what the article does. It uses 3 alternatives, it messes with very a strange score system, for which the statistics are difficult, and asks the question “do you think this is more pleasant than that and that?” – because this is what you ask when you ask people to identify which one is the original, which one is at 256 kbps, and which one is at 128 kbps. They will say that the most pleasant is the original, next comes 256 kbps, and then 128 kbps.
Then they say “our
musically trained test listeners could reliably distinguish the poorer quality MP3s at 128 kbps quite accurately from either of the other higher-quality samples.” Well, IMHO, only deaf have problems with hearing the clear pumping frequency shift and distortion (Doppler Effect reminiscent of Leslie speaker sound), especially on cymbal’s sound at 128 kbps MP3. Some pelope even like it.
In summary, if that article was to be published in a peer-reviewed scientific paper, and I was its referee, then I wouldn’t let it through.