White Denim, Electric Ballroom, London

The last time I saw White Denim they were a formidable psychedelic power trio who delivered one of the most blistering aural assaults I'd heard in ages.

With the addition of second guitarist Austin Jenkins they're no longer a trio, but the power element has, if anything, been cranked up a notch: at times during their set, it was hard to see how things might have been made any more intense, or where an extra note might have been squeezed in, so crammed was the sound.

As with Cream, it sometimes sounds as if everyone's soloing at once, yet here the individual threads intertwine magically, with Steve Terebecki's bass providing sinuous counterpoint to Jenkins's and James Petralli's braiding skeins of guitar, while drummer Joshua Block drives things along like a coachman whipping his horses to exhaustion. But unlike Cream, the improvised sections are comparatively few and far between: this complex web of sound, segueing seamlessly from one song to the next, is all intricately worked out and rendered with the meticulous math-rock industry of virtuoso proggers like Yes and King Crimson. It's a sort of musical equivalent of fission, all elements adding to the critical mass.

Yet there's also something looser going on at the music's heart, prefigured by the jeans and rolled-up shirt-sleeves look – and the way Petralli's guitar case is left lying centre stage throughout, as if he's just sound-checking. It's a kind of chummy, whimsical air which recalls the Meat Puppets or, particularly on the material from the new album D, the Grateful Dead. Like the Dead, the set opens with a few wisps of sound, before congealing into the muscular groove and undulating, serpentine guitars of "It's Him", followed without pause by "Burnished" and "At the Farm", one of several candidates for the band's own "Dark Star".

Before long, the moshpit is a frenzy of activity as the band power through favourites like "Shake Shake Shake" and "I Start to Run". Terebecki all but plays the strings off his bass during the wah-wah malestrom of "El Hard Attack", and summons memories of Zep's "How Many More Times" during "Mirrored and Reversed"; but the wheedling anthem "Drug" brings the set full-circle, back to the Dead associations with which it began. By the end, both band and audience are left drained, delirious and exhilarated, as if we've all just been through a gruelling assault course – which, in a way, we have.