Surprisingly, piano technicians are generally okay with pianists preparing instruments in the manner prescribed by John Cage in his Sonatas and Interludes for Prepared Piano. If you've never done it before, it takes about two hours to get everything set up inside the piano.Once you play Cage's Sonatas with the preparations for the first time, the sound that comes out is completely different from what you had practiced without the preparations.
Boris Berman plays Sonata II:
Bobby Mitchell plays Sonata V:
