[philip]

some more info on the subject, taken from Phase, Time and Distortion in Loudspeakers
I do not answer for this articel but I find it useful.


Phase Audibility
The audibility of absolute phase is nil.

I must explain this further, as this is a somewhat contentious issue. It can be proven in ABX tests that there are some signals where the difference between a non-inverted and inverted signal is audible. Certain waveforms and instruments are highly asymmetrical, and if listened to in isolation will sound different if the phase is reversed. The difference is not subtle, either - it can be very pronounced. This is much more likely to be a result of loudspeaker driver behaviour than anything else, and the "correct" phase is anyone's guess - should it be inverted or not? We don't know the answer, since we will be unsure of what the instrument sounded like "live" - it is possible that neither the inverted or non-inverted recorded signal will sound like the original, so the point is moot.

The key issue here is that if we listen to a saxophone (a good example of an asymmetrical waveform) with the phase normal then reversed, all we hear is a difference - there is not necessarily a "right" or "wrong" phase, since it depends on the way the instrument was miked in the first place. If the period between listenings is extended to a few minutes, the chance of us hearing the difference will be minimal, and we still won't know which is "right" and which is "wrong" - all that this proves is that there is a difference, and it only becomes audible with some instruments.

This is probably the only case where an ABX test proves something that is not relevant in the general sense - so yes, absolute phase can be audible, but it is (generally) irrelevant. While it may be possible to pick a difference, it is only a difference - neither sounds better than the other.