A vinyl re-release of four pieces for prepared piano, originally from 1978, played by Hermann Keller himself in a non-traditional way. Including 'Ex Tempore VI und Anrufung', 'Ex Tempore I', 'Schwebungen-Brechungen', and 'Ex Tempore VII'. Hermann Keller is the prototype of a circumspect and restless experimenter, an improviser who turns out unprecedented inventions while holding his audience in thrall. One of his favorite occupations is to play ex tempore at the piano, attacking the keys and the…