Alex Twisleton-Wykeham-Fiennes Wrote: > On Fri 13 January 2006 01:57, P Floding wrote: > > JJZolx Wrote: > > > I've added the following comment to bug/request #1976. Hopefully > it > > > would cover all needs in this issue: > > > > > > > > > If it's important to you, then vote for the bug. Don't just CC > > > yourself. By voting you automatically get CC'd with all new > comments > > > and changes to the bug. > > > > > > http://bugs.slimdevices.com/show_bug.cgi?id=1976 > > > > JJZolx, thanks for your addition! I will vote for it, of course! > > > > Regarding some of the other comments above: > > > > Yes, I'm talking about absolute phase, not phase error between left > and > > right channel -if you can't heat that, you have a seriously poor > system, > > or hearing, as that totally defocusses voices, for example! > > There is a school of thought that says that the fact that the inversion > of a > some steady state non-symmetric signals being audibly different (which > > appears to be the most common proof of absolute phase being important) > is > proof that loudspeakers are not quite as linear and symetrical as they > should > be so maybe with a "perfect system" it would be a different story? (I > jest > slightly) >
Sure. However, we only have loudspeakers, and if they sound better with correct polarity, then that is what we should use! Personally, I believe, based on basic physics, that an initial transient that pushes rather than pulls would sound more realistic. I have seen more sophisticated theoretical discussions on this subject, having to do with doppler effect, etc, if I remember correctly. (Since air is a compressable medium, the air does not behave exactly identically in the compression phase as in the expansion phase when "vibrating" to a sound. I'm admittedly on thin ice now, regarding my own knowledge in this area.) Alex Twisleton-Wykeham-Fiennes Wrote: > > > > About the comment on instruments being pointed downwards: It doesn't > > matter for this issue at all, since the microphone would be > positioned > > in the direction the listener would be, and hence the microphone > will > > receive the polarity that the listener would receive. > > > > For close-micked multimicrophone recordings, polarity switching may > not > > make any difference. However, I have noticed that even on some > studio > > recordings it can still make a difference. Perhaps all tracks were > > recorded correctly, but some late stage in the mixing/mastering > inverts > > the ready-mixed signal inadvertently. > > I would be amazed if any multi-microphone recording (even so-called > time-aligned multi-mic classical recordings) came anywhere close enough > to be > phase coherent in themselves so any improvement would be due to chance > > psycho-accoustic affects rather than any "absolute correctness". > I'm not so sure. If each channel of a multi-mic recording is in correct phase, then the result is simply a superpositioning of these channels. Sure, individual distances (time and volume), and low level ambient information shared between the channels would be a bit of a mish-mash, but the fact would remain that the leading edge of transients from all channels (from the instruments dominating each channel) would be in the correct direction. Alex Twisleton-Wykeham-Fiennes Wrote: > > > > It is true that you system has to be pretty good to hear the > > difference. I had difficulty hearing it before i got the TacT RCS. I > > imagine headphones would do the job at a lower cost, however. > > Just out of interest - are you switching your phase before you go into > the > TacT or after (ie on the room corrected signal)? Do you have an option > on > this? I would be very interested to know if there is a difference on > your > system. I could imagine that the room specific processing that the > TacT > performs on the digital signal would be much more sensitive to absolute > phase > than the signal from the source that is being fed into the processor. > > Alex That is an interesting point. However, if you regard the TacT pre, the poweramp, and the speakers as a "black box" (let's say, a digitally corrected active loudspeaker), then this question would be pointless. If the corrected system gives much better performance with a input signal of the correct polarity, then that is what we should use! I do understand your point though. Is the digital room correction doing something that exagerates polarity differences, more than a perfect phase coherent speaker in an ideal listening room would have done? I don't know. I do know that people with very good systems, but no digital room correction, report the same type of audible differences between listening to correct or incorrect polarity. (I should say that "correct" here means, best sounding! I have yet to verify that the best sound corresponds to any recording's correct absolute polarity. Something that would be an interesting project! Correlating phase-data for various CDs with other audiophiles might be a good start.) Also, I do not know if the polarity inversion of the TacT is done before or after the digital room correction processing. -- P Floding ------------------------------------------------------------------------ P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=19961 _______________________________________________ Discuss mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/discuss
