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Without blind ABX tests, it remains an open question.
Cons : technically, the sound can't depend on the burning quality, as
1-The CDRs supposed to have a bad sound are always checked to be error free.
2-The jitter on the CD can't affect the jitter in the DAC
No blind ABX test is known.
Pros : a lot of user and professional reports, often hearing a bad sound while they expected a good one (that would rule out the psychological effect), investments from CD manufactutrers in jitter free CD Recorders for CD manufacturing, hypothesis about the clock stability of the DAC when a bad CD is read.
However, the cons are qualitative arguments, not quantitative, and the pros are weak (investments can benefit the compatibility and longevity of pressed CDs rather than sound).
None of them are convincing.
Here's how it should be tested :
Find someone willing to run the test, who claims to hear easily the difference. The test must be run on the hifi that shows the difference.
In the ABX system, the test is divided into sessions. A and B will be the compared items (original and copy). They are known to everyone.
In each session, the source X is randomly chosen between A and B. The listener must not know which one it is. He can listen A, B, and X at will. Then when he is sure, he can give his answer and say if X is A or X is B. The answer is noted, and the next session begins : a new X is chosen randomly, and he must recognize it again.
8 sessions are a minimum, otherwise, the right answers can be found by chance. 16 is a good number. Even 15/16 is a good score.
To test CDRs, the person must be blindfolded (let the ears free !). Someone else will toss a coin to choose between the original and the copy.
It is essential that both CD are outside the CD player when the listening is switched between A, B, or X, otherwise, the person will know which is which, listening if the tray opens when switching from A to X, or B to X.
Therefore, when any source is asked, open the tray, take the CD, even if it is the one to play next, put it in its case. Then take it again and insert it in the player to play it.
The ABX test is difficult, it is important, in order to recognize X properly, to make some pauses between the sessions if the test is too long, and for the listener only to give an answer when he is absolutely sure of it. When he's not sure, let's make a pause and go on later.
Until no such test is run, I'm not convinced by any side.
Pio2001
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