Vetter came from the recorder, where his work on multiphonics and microtones drew new pieces out of Stockhausen, Kagel and Bussotti. Here it is pianos and overtone singing, the upper partials pulled away from the fundamental until they read as a separate line.
Michael Vetter's improvised overtone songs with tambura, Gesänge der Nacht I and II, recorded on 12 and 13 September 1987 in the Cistercian abbey of Le Thoronet.