A dependable pleasure for anyone with a predilection for heavy psychedelic rock, the latest tour by this enthralling Washington DC-raised combo finds their slow-burning paisley cacophony in particularly rude health. The heady sound the trio conjure up is now at once more stripped-down and more vivid, and, despite its clear debts to vintage cosmic rock, entirely their own.

An additional treat tonight comes in the shape of this tour's terrific support act, Baltimore's Arbouretum. Essentially playing very, very heavy folk, Dave Heumann's hypnotic, repetitive vocal melodies are clear, grand and hymnal, and at the risk of stretching the arboreal theme, it is quite possible to hear the solid, ringing chords and exquisite, pealing twin-guitar solos as the trunk and canopy of their unique sound. Pretty special.

But Dead Meadow are still the main draw. In contrast to Arbouretum's strong, resonant melodies, this is something much more fluid and inconstant - not so much written or composed as created by some kind of musical Brownian motion. Long, loose riffs are teased out through waves of wah-wah and feedback, more often than not at a woozy, lolloping pace. Jason Simon's aqueous vocals sound like classic 60s British pop taken to freeform psychedelic extremes.

Rhythm is the main constant, and drummer Stephen McCarty treads a masterful line between nailing it down and filling it out. Inevitably for a band keen on improvisation, there are lulls, and a shorter set tonight might have harmed no one. But the intoxicating peaks they often reach put them in the major league of noisy, out-there rock'n'roll for this or any era.

· At Thekla, Bristol, tonight. Box office: 0117-929 3301. Then touring.