BJ Cole / Voltage, Cargo, London

Resonance Radio were holding a free gig, so Cargo's transformed underneath-the-arches space was packed. Found on 104.4fm, the station is operated by the London Musicians' Collective, and is dedicated to sounds that are beyond most people's ken. It's also streamed via www.resonancefm.com. The music of rattling collection tins greeted each new arrival and various Resonance DJs were spinning cuts before and after the live acts.

The headliner BJ Cole was on first, seated at his pedal steel guitar. You'll have heard him before: he's a session- man supreme, heard in the old days on Scott Walker's "No Regrets", and more recently on tunes by Björk and Beck. At the other end of the alphabet, he's been in the studio with Link Wray and Tammy Wynette. When he's got the time, Cole releases albums under his own name, aided by the Transparent Music Ensemble, co-writing material with the veteran Van Der Graaf Generator keyboardist Guy Jackson.

BJ's set is nowhere near to country and western, opening as it does with a looped-up number from his Stop The Panic collaboration with Luke "Wagon Christ" Vibert. The pair played at last year's Big Chill, maintaining Cole's commitment to completely revising his approach as time rolls onward. B J draws out elongated, sliding phrases, against a backdrop of jittery beats and mangled basslines, then he shunts into a complete turnaround, immersed in his more accustomed ambient fluids. The talkative audience don't appear to be paying much attention: that's the definition of ambient music, I suppose.

At the end, singer Laura B enters, changing the mood. She dreamily coos along to Cole's tear-soaked strings, slinging a Hawaiian garland around his neck to underline where the music's coming from: Nashville and Honolulu, the twin cities of the floating note. Cole, however, would have benefitted from being louder in relation to his backing tracks: he would come across more effectively in an intimate theatre, this setting was too distracting for his introverted demeanour.

Voltage were booked as a definite contrast, a power trio devoted to the art of improvised rock. They'd threatened to erupt into guitar-slashing, no-wave chaos, but decided to drift around aimlessly instead. Singing bassist Sharon Gal adopts the cathartic vocal approach of Diamanda Galas, holding powerfully sustained notes some distance away from the microphone. At times, she seems too mannered, too gothically self-aware as she mutters and babbles doomy streams of unconsciousness. When she tootles her flute, this makes the band seem like a loose bunch of hippies rather than the desired hot-wire punky threat. There are times when the trio start to lock together, usually prompted by drummer Dennis Austin's tumbling free-jazz patterns intertwining with Moshi Honen's opened-out guitar strafes. After 30 minutes, Voltage start to mesh, but in a 45-minute set, this is a tardy development.