Plus or Minus, for two pianos and electronics, is a 50–minute free realization of Stockhausen’s open score composition of the same name from 1963. It refers to all 7 pages of the open score and utilizes two layers of activity, each of which is represented by one piano. The pianos themselves are transformed with transducer speakers placed throughout a piano’s chamber so that sound is essentially “spatialized” within. Single piano tones emerge and disappear continuously between transducer speakers...