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Path: utzoo!watmath!watdcsu!herbie
From: herbie@watdcsu.UUCP (Herb Chong [DCS])
Newsgroups: net.audio
Subject: Re: stereo
Message-ID: <1059@watdcsu.UUCP>
Date: Sun, 3-Mar-85 14:18:44 EST
Article-I.D.: watdcsu.1059
Posted: Sun Mar  3 14:18:44 1985
Date-Received: Mon, 4-Mar-85 06:33:24 EST
References: <630@houxa.UUCP> <191@moncol.UUCP> <86@vice.UUCP>
Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS])
Organization: U of Waterloo
Lines: 36
Summary: 

In article <86@vice.UUCP> winkg@vice.UUCP (Wink Gross) writes:
>"image height"?  Would someone please explain how stereo with only
>two channels could convey any spatial information on an axis perpendicular
>to the line between the speakers?
>
>				     Wink Gross
>				     Tektronix

the height that can be heard is produced by psychoacoustics at work and
has little, it any correlation, with the actual vertical placement of
the instruments.  it seems that when pure tones are heard, certain
frequencies seem to come from specific directions no matter where the
actual sound source is.  speakers with vertical imaging do this to some
extent.  also, speakers are not ideal point sources with the tweeter and
bass drivers separated.  phase differences between different parts of
the spectrum of the played instruments emulate to some extent what happens
when these instruments are played close to reflecting surfaces of different
sound absorption properties.  since there are no such surfaces in the right
places, the eyes force the brain to do other things to come up with something
resembling reality.  you end up getting the illusion of vertical placement.
only good recordings with well recorded ambience and extremely low
distortion will provide this effect, and excellent equipment is required to
reproduce it.  simpler microphone techniques tend to show this better.

Audio, a year or so ago, had a very good article on psychoacoustics.  more
importantly, they have citations at the end of their articles so that you
can do more research.  i'm sorry, but i don't have the issue number or date.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

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