From: John Woodgate
Subject: Re: Bullshit wins v. science
Date: Tue, 5 Nov 2002 11:17:18 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Tue, 5 Nov 2002 12:50:55 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Paul Burke wrote
(in <3DC78479.F3CEC5FB@scazon.com>) about 'Bullshit wins v. science', on
Tue, 5 Nov 2002:
>John Woodgate wrote:
>> Strictly, that is 'polarity', not phase. Only a small percentage of
>> people can hear it. The difference is said by those who can to be
>> subtle. It should occur with male voices, as well, since the waveforms
>> are somewhat unsymmetrical. But most audio processing and most
>> loudspeakers introduce phase shifts that tend to mask the polarity
>I once attended a demonstration (by BBC engineers) in which a piece of
>music was being played, and suddenly they reversed the phase.
Ah, now, it depends on what you mean by that. Was it a 2-channel stereo
demo, during which they reversed the polarity of one channel?
> The heads
>of virtually everyone in the audience suddenly turned, in the same
Through 180 degrees? Horizontally or vertically? (;-)
>So, it would seem that most people are sensitive, but to the
>dynamics of the phase, not the static relationships.
If you reverse the polarity of one channel of 2-channel stereo, the
sound image shifts from substantially between the loudspeakers to a
point beyond the loudspeaker that is louder at your listening position.
Everyone who doesn't have a large difference in hearing acuity between
the two ears can hear that. It is not the same as detecting polarity
reversal of a monophonic signal or simultaneous reversal of the polarity
of all channels in 2 or more channel stereo.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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