From: wex@pws.ma30.bull.com (Ren and Stimpy Live.)
Subject: Re: 3-D Sound imaging systems (a clarification)
Date: 2 Dec 91 17:01:32 GMT
Organization: Bull Worldwide Information Systems Inc.



In article <1991Nov23.002313.9751@milton.u.washington.edu> good@baviki.enet.
dec.com (Michael Good) writes:

   I've not had a chance to A-B the Convolvotron and Focal Point
   side by side.  In demos at different times in different places, I
   found their 3-D effect about equivalent, which is to say OK
   but not great for me.  If I were a subject in one of Beth Wenzel's
   experiments, I suspect I would be one of those people who
   has a high percentage of front-back reversals and difficulty
   in Z-axis localization.

You'd have lots of company.  In conversation with Bill Gaver & Sara Bly at
CHI'91 it appears that up to 40% of the population has these problems to one
extent or another.

   Alan's observations are interesting, and I would like to
   hear from more people who have tried out both systems.
   How would you describe their relative advantages and
   disadvantages for your work or research context?

By "Alan" I assume you're talking about my comments on Focal Point.  I also
have not had the chance to use them side-by-side on the same application,
but I did go from the Boeing VR setup (using a VPL/Convolvatron rig) to the
Focal Point setup at CHI'91's Interactive Experience.

The Focal Point demo may have sounded better because it had only sound so
there were not as many distractions.  But I liked the fact that I could hear
the sound of a chopper taking off and the sound appeared to "rise" from my
point of hearing.  By contrast, the virtual airplane in the Boeing demo had
engine sounds that I could locate to the left and right, but didn't appear
to move "down" when I flew my viewpoint above the aircraft.

Again, let me emphasize that there were an incredible number of confusing
factors, not least of which were the earphones.  The Convolvatron uses the
large padded ones; Focal Point was using the small "bud" style popular on
various walkman-type products.  I like the latter type better.

Also, I do not have the technical proficiency to evaluate which set of
algorithms is better.

--Alan Wexelblat			phone: (508)294-6120
Bull Worldwide Information Systems	internet: wex@pws.bull.com
Billerica, MA					  wexelblat.chi@xerox.com
Only drugs make you as happy as the people in the ads.