Stephen O'Malley (Sunn0))), KTL), Daniel O'Sullivan (Ulver, Mothlite, Guapo), Kristoffer Rygg (Ulver), Steve Noble (N.E.W., Company, etc). En Form For Blå documents the continued evolution of this unlikely collective, a collision of players from various avant, improv, metal, and "other" threads who together make a unique and arresting sound. Documenting three gigs in Oslo recorded in 2010, the music is deep and weird, with liquid sounds juddering around the occasionally identifiable percussion or Rhodes motif. Moving from an occasional/studio group to a frequently working live act, Æthenor has somehow kept their sound intact, taking the musique concrète-style transitions and "what's that sound" ethos of their three previous efforts directly to the stage. Noble, having spent a couple of decades playing drums with Derek Bailey and other well-known UK improvisers, moves the music along subtly, keeping much of the focus on the burbling sound mass. O'Malley's guitar, an instrument of extreme viscera in Sunn0))), is used with restraint, providing occasional low menace but mostly mixing it up with O'Sullivan's thematic lines and Rygg's sound treatments. The overall effect is atmospheric rather than sedate - something like a modern, small group version of Miles Davis' classic "He Loved Him Madly" or Nurse with Wound's "Spiral Insana." Other than Supersilent, it's hard to think of anyone really working this sonic vocabulary - this is a bold engagement from players who are well-known for completely different reasons from the strangeness heard here.