This is our most complex design.

A lot of ideas were kicked around on how to design a mechanism that would allow the tension on a drumhead to be changed with a foot pedal. We probably should have looked up how a kettledrum operates but we didn’t think of it at the time. What we came up with works well. 

We also tried different head materials in an effort to maximize the dynamic range. Various thicknesses of elastomers (natural rubber, nitrile, ethylene propylene diene monomer [EPDM], butyl rubber) did allow for a wide tonal range but only for a short time before failure. We settled on Mylar, which is a commonly used synthetic drumhead material. Goatskin also worked, but the sound with Mylar was more interesting.

What does it sound like? Kind of like crossing a tom–tom with a theremin. It’s a weird thing. Maximum verbosity!