Path: utzoo!mnetor!uunet!portal!cup.portal.com!Michael_M_Butler
From: Michael_M_Butler@cup.portal.com
Newsgroups: comp.sys.amiga
Subject: Re: Sonic Tomfoolery
Message-ID: <3511@cup.portal.com>
Date: 27 Feb 88 00:48:40 GMT
References: <319@ardent.UUCP>
Organization: The Portal System (TM)
Lines: 24
XPortal-User-Id: 1.1001.2469


The psychoacoustics of placement are tricky.  When the usual information
(phase, delay, etc.) gets scrambled enough, the auditory perception system
"gives up" and you wind up with the sound seeming to come from "nowhere"
(with headphones on, it sounds as if it's coming from "inside your head").

If you're working with a sound which is intended to move from (say) directly
in front of the listener around to the listener's left and then continue be-
hind, the factors to bear in mind are that the sound from dead-ahead will
compare with the sound from dead-astern as subtly different.  The pinnae
will tend to cut treble and make the sound a trifle fainter.  There may be
other effects; I forget.  I think Chowning (at Stanford?) did some work on
this around '76 or '78.

Also bear in mind that the power ratio of the L and R channels has to vary
in a way consistent with physics if you want the motion from dead-ahead to
abeam-portside to sound right.  A little trig ought to do ya.

I'm not sure about percieved attack and decay.  I suspect that you're not
going to include simulated ambience in this rev (go ahead, prove me wrong(:D)).

Thanks for audiotools, Mr. Peck!

Michael [My fancy trailer is at the cleaners] Butler
Xanadu Operating Company