Eruption, there was AMM at their most unhinged.
Wishing to stake out territory far beyond free jazz, Eddie Prévost, Keith Rowe and Lou Gare hooked up with pianist/composer Cornelius Cardew and percussionist Christopher Hobbs to make this glorious racket. Prévost continues with versions of the group to this day. First released as a an extract on one side of a shared LP, more of the Crypt performance was given a double-LP release in 1981 before the complete recording came out in 1992 on this 2-CD edition.
Fades where they occur are when tapes ran out; other than that, all 109 minutes of the show are here for your, erm, enjoyment, and actually it's not all quite as extreme as it starts out. Long passages of meditative, near-ambient formlessness crop up at intervals; often I just pick a random 20 minute section of The Crypt to listen to, and always find something new to focus on.
alt. link (zippy) CD1
alt. link (zippy) CD2