This video is a demonstration of a unique control voltage controller, The Magnetic Table, created by Jon Sonnenberg.

Here’s what he has to say about The Magnetic Table:

There are 2 control voltage outputs for this device; one for the X axis, and one for the Y.  They vary from 0 to 5 volts.  These can be used to change any parameter in a synthesizer or effects system to make interesting sounds.  For instance, the X axis could control the pitch of an oscillator, while the Y axis could control the volume.  Another example could be the X axis controls a delay time, while the Y axis controls the feedback of the delay unit.  A third example (and a little more abstract) is to have the X axis control the length of a sequence pattern, and the Y axis control the tempo of the sequence.

One interesting thing about using the magnetic table to control sound is that when the pendulum passes over a magnet with a pole that attracts the pendulum, it overshoots a bit, then swing back toward the magnet and overshoots again, continuing to oscillate in a damped, simple harmonic motion.  If the magnet is stronger (you can use larger magnets or stack them to make them have a stronger attraction or repulsion), then this oscillation is faster.

See Sonnenberg’s site for more details.

via reader Lewis Fisher