Prepared piano

Its invention is usually traced to John Cage's dance music for Bacchanale (1940), created for a performance in a Seattle venue that lacked sufficient space for a percussion ensemble.

Typical of Cage's practice as summed up in the Sonatas and Interludes (1946–48) is that each key of the piano has its own characteristic timbre, and that the original pitch of the string will not necessarily be recognizable.

Additionally, notable contributors to the subsequent repertoire include Lou Harrison, Pauline Oliveros, James Tenney, and Christian Wolff.

After some consideration, Cage said that he realized it was possible "to place in the hands of a single pianist the equivalent of an entire percussion orchestra ... With just one musician, you can really do an unlimited number of things on the inside of the piano if you have at your disposal an exploded keyboard".

It was built as part of a graduate thesis project at California State University Dominguez Hills by Bob Fenger (1983), a student of Richard Bunger (author of the Well Prepared Piano).

Secondary control parameters allow extraction of vibration and sound phenomena from the kinetic oscillators through a series of proximity microphones and PZMs (piezo-electric contact mics).