Listening to a piece by Hauschka can be deceiving: What sounds like an ensemble of musicians and instruments is just one man, performing at one piano. His real name is Volker Bertelmann, and he hails from Dusseldorf, Germany, where he works with his "prepared piano." He wrests disruptive sounds from the instrument's 88 keys by outfitting the strings or mallets with objects such as ping-pong balls,
