My love is both computer graphics and sound.  What an odd mix.  After experiencing the CAVE many times and realizing that it could be made better by the use of other sensory output.  I came up with the idea of using sound in the CAVE - no not just as audio cues but as something you could feel - Tactile Sound.  So I proposed to SIGGRAGH in 1996 the idea of the VibraFloor.  Originally conceived using massive subwoofers, the idea changed to incorporate the use of Clark Synthesis Tactile Sound Tranducers.  The VibraFloor was debut at SIGGRAPH 1996 in the Digital Bayou.  An environment comprised of the most interesting and innovative projects utilizing computer graphics.  Well obviously sound has nothing to do with computer graphics except when it is combined.  The VibraFloor was my first Virtual Instrument.  A musical instrument that utilized CAVE technology but did not need an entire CAVE's worth of hardware to operate.  The actual amount of hardware used was minimal compared to most of the other exhibits in the Digital Bayou.  Strangly enough the booth that I presented in turned out to be one of the most popular booths of the show.  The name of the presentation was Vibescape.  The software for Vibescape utilized sound samples on an SGI Indy that were triggerable based upon location in 3D space ( a 10 by 10 foot cube).  the sounds were the equilavient to 2 foot spheres mapped in 2 layers.  Each layer was a matrix of 5 by 5 spheres in X and Z, for a total of 25 sound spheres in each layer.  Two layers gave me a total of 50 possible sound locations in addition to these staticly placed or mapped sound spheres there was also 25 "floaters".  Floaters were sounds that randomly moved throughout the space.  So even if the reciever or sensor did not get moved the floaters found the sensor.