From: well!oster@well.sf.ca.us (David Phillip Oster)
Subject: Re: Binaural stereo
Date: 17 Jun 90 03:23:43 GMT
Organization: Whole Earth 'Lectronic Link, Sausalito, CA



The current issue (june, 1990) of Electronic Musician, ("The Music of the 
Future") has an article on audio virtual realities. They calibrate the device 
by putting microphones in your ear canals, placing you in an an-echoic room,
and moving sound emitters around.

Once calibrated, the system can localize sound emitters in the virtual
space about your head.  It can also simulate room acoustics: draw a wall
with your data glove, and hear the echoes of the sound emitters in your
virtual space change, as the system accounts for the wall.

One use for this: Tom Furness at U. Wash said in a speech that if you 
need to get a pilots attention during an emergency, a real good way is to
play a tape of his young daughter, from a virtual distance of 6" from his
right ear, saying, "Daddy, your landing gear are still up."  People listen
harder if the sound seems to come from inside their personal space.

The imaging system needs enough DSP power to Fourier transform the original
waveform, manipulate for stereo imaging in the Fourier domain, and transform
back, in real time so it can keep the virtual position stable as you twist
your head. A pair of cheap DSP chips are enough for the task.

Furness also said that DSP trickery can also be used to take a stock Polhemus
6-degree of freedom sensor from 6 position samples per second to > 100.
This makes the virtual world substantially higher quality.

This must be virtual reality month:
Summer 1990 Whole Earth Review
June 1990 Electronic Musician
June 1990 Smithsonion (article on Media Lab.)

and more I'll bet, all chose this month to cover V.R.

Thanks to the guys at Tektronix. They sent me the material on their commercial
system for the Mac II. It is a 16" Color display that provides separate images
for the left and right eye at 60 frames per second each. It comes with software
for modelling molecules and representing them in a number of 3-d ways.
Out of my personal price range though: "Stereo Add-On System $33,990".
-- 
-- David Phillip Oster - Note new address. Old one has gone Bye Bye.
-- oster@well.sf.ca.us = {backbone}!well!oster