Here’s one for Tom, or anyone else interested in doing ambisonic sound recordings. It mounts four inexpensive Panasonic electret microphones into a tetrahedral array to record sound that can later be processed for surround or other spatialization effects. Seems pretty cool, and they even include the patterns for PCBs that can be cheaply manufactured by ExpressPCB. Nifty!
There is a new URL for the Ambisonic Microphone Exp2 Documents page:
http://webspace.utexas.edu/~dth245 .
Dan