AMMMusic (1967)
AMM are a British free improvisational / experimental group founded in 1965. AMM have been cited as being one of the first musical outfits to play music completely in contrast with any established musical genre. Although AMM remain incredibly obscure to the collective, they have been very influential to the artists of improvised and experimental music.
Consisting of Cornelius Cardew, Lou Gare, Eddie Prévost, Keith Rowe and Lawrence Sheaff, AMM continue to preform (although, Prévost is the only original member remaining).