Build spring reverb?

[Steve A.]

I remember reading somewhere that in the usual Accutronics spring tank, the tranducers are actually twisting the springs, rather than pushing/pulling or wiggling. That is to say, the mechanical 'signal' is a torsional wave rather than a longitudinal or transverse wave. But of course now I can't find a source on that.

Does it actually matter whether the spring is being driven with torque/rotation or piston action? My gut says that the torsional drive would be less sensitive to mechanical interference from nearby speakers, but again, no evidence to back that up.

It would be very interesting to look at the patent application(s) for Accuratronics spring reverb... anybody have a patent number?

Steve Ahola