I've two observations to contribute: 1) I remember a demo by Linn in the mid 80's where they reversed the polarity of the speaker cables to demonstrate the effect on perception of surface noise from vinyl. I had to agree it made a noticeable difference to how bad the pops and clicks sounded. It didn't change the rest of the music for me. The offered explanation was that the most annoying "clicks" were caused by wall damage that was physically predominantly in one direction with regard to the movement of the stylus.So, the initial transient (which is pretty much all you hear) is the stylus and thus the speaker cone moving either out or in depending on absolute phase of the post-stylus electrical chain (the transient is asymmetrical with regard to 0V and so the "recoil" movement of the cone coming back through zero to create a whole-period waveform is NOT the same magnitude as the initial rising wave. This is hard to describe in words - imagine a sine wave where the bit above the line is bigger than the bit below it. If you've ever edited clicks out of a vinyl transfer on a computer you'll know what I mean.
Anyway, the theory was that the speaker (any speaker?) reacts slightly differently to these quasi-DC non-musical transients because of the effects of cabinet air pressure loading and other anomolies in the physical construction of the speaker itself and that this was enough to change the sound of the transients. Not sure where this leaves us regarding digital sources that should not have these sort of transients in them. I can't hear any difference switching the phase on my TACT 2.2x or by reversing the speaker cables... 2) If there is significant DC across the speaker coils, the speaker cone will not be sitting in the 0v stationary position as its designer intended. This could introduce a "constant" asymmetry in response which would be absolute-phase sensitive - especially in closed box or port loaded speakers. This would be audible with real music. I'm not sure what significant would be in this context because as has been stated its not clear what the limits of human perception are. However, it might be worth checking for DC, as this would provide a rational explanation for absolute phase differences. Could this be simulated with a manufactured WAV file?. Also, could DC elsewhere in the chain cause this asymmetry - perhaps in the current draw of the power amp supply rails? Food for thought anyway... -- Phil Leigh ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=22118 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
