The Penn And Teller Spirit Chair

The Penn And Teller Spirit Chair, aka The 1994 MIT Sensor Chair is an interesting theremin variant.

Six capacitive sensors are used to control MIDI outputs - no heterodyning. There is one under each of the player's feet, like Z-Vex (http://zvex.com/effects.html) Probes, and four at the corners of a rectangle for the hands.

And - here's the curious bit - a plate on the seat of the chair fed by an RF oscillator, so that the player is not a passive, grounded capacitive object as usual.

Here (http://web.media.mit.edu/~joep/MPEGs/penn.mpg) is a video of it in use.

Here (http://web.media.mit.edu/~joep/TTT.BO/chair.html) is more info. (A lot more. Especially in the pdfs at the end of the article.)

Thanks Gordon!
This is an absolute treasure chest of information - and has lots of similarity to what I was doing on Epsilon, only on a grander scale! -
The article "Musical applications of electric field sensing" is by far the most comprehensive coverage of this subject that I have found - despite having bought some big expensive books like Curtis Roads "Computer Music Tutorial" which goes into controllers in some depth.

It is a good article. They had me on the first sentence.

[i]The Theremin was one of the first electronic musical instruments, yet it provides a degree of expressive real-time control that remains lacking in most modern electronic music interfaces.[/i]

Yes.