(I) TAPE

LOOPTY LOOP

Erik Satie

Musique D'Ameublement

Vexations

Fritz Pfleumer with his magnetic tape recorder.

Read about the history

also wiki 

Karlheinz Stockhausen

Kontakte

Delia Derbyshire

Pierre Schaeffer

more reading

Terry Riley 

Time Lag Accumulator

Pauline Oliveros

Robert Fripp

Fripp & Eno

Brian Eno - Discreet Music

William Basinski 

Aki Onda

more Onda

interview

Artifact / Art in fact.