Hydra Head Records founder and recent Seattle transplant Aaron Turner will do double-duty at this show, providing guitars and effects for local atmospherist Mammifer as well as fronting his own band, Isis. On the surface, Isis and Mammifer appear to fall on opposite sides of a huge divide: Isis is heavy; Mammifer is delicate. But both acts rely on ambience to such a degree, and with such command, that they transcend their respective genre trappings. For all its metallic space-rock crunch, Isis arguably hits hardest through its use of dynamics, often employing long, drawn-out quiet sections to galvanize the listener. Likewise, Mammifer’s steady, down-tempo textures overflow with brooding and hit hardest in places where the music is most sparse. If Isis represents the tense, slow build-up to an explosive climax, Mammifer’s work sounds like the aftermath as the smoke clears and regret sets in. With Thrones, Mammifer. All ages.

Sat., June 20, 8 p.m., 2009