When two of the international free-rock scene’s most volatile improvisers convene for a real-time shahi baaja-and-drums jam session, cautious listeners might anticipate a block of anemic, noodly half-utterances. Chris Corsano (Six Organs of Admittance, Paul Flaherty, Thurston Moore, and more) and Mick Flower (Vibracathedral Orchestra, Sunroof!) beat these dire forecasters into submission on their first duo outing. For one thing, Flower’s shahi baaja — a Japanese dulcimer/autoharp hybrid — is amplified, and he casts from it rapid-fire shards of raw electricity. He then strings these salvos together in a fluid, Coltrane-esque fashion, rending sheets of sound from sheet metal. Meanwhile, Corsano’s incendiary drumming acts not as a bully, but an enraptured pulpiteer, unleashing jubilant cascades of percussive exhortation. The kids will call this jazz-baptized Lightning Bolt; elder statesmen will recall hearing Ascension or The Blue Humans for the first time.