Percussionist Zach and guitarist Grydeland founded the excellent Sofa label in 2000. Their second duo release presents a fascinating pair of improvisations caught last year in Geneva and Oslo . Grydeland characteristically rings harmonics and picks bright, steadily mutating figures on metal stringed acoustic guitar. Infrequently Zach adds decisive beats, generating cymbal shimmer or low friction, eliciting a drone from his Indian sruti box or drawing brilliant chimes from small bells. Controlled feedback from Grydelands electric guitar plays its part in what seems to be a conscious process of redefining the performance space, modifying its feel or adding significant decoration while the focal point, centre stage, may be left suggestively vacant. On CD these improvisations, five months apart in different cities, both convey an element of auditory set design that doesn't just frame but actively constitutes the music.