John Cage's prepared piano

In Figure 5.34 we showed a spectrogram created from a recording of John Cage's Piano Sonata II on a prepared piano.  The following video by Stephen Drury of New England Conservatory is an excellent description of how a piano is prepared using Cage's method:

We are grateful to Stephen Drury and New England Conservatory for granting us permission to include this video in our web site.