AS A teenager in the late 60s, Robert McFall would while away the hours with Frank Zappa's genre-smashing Freak Out!

and Captain Beefheart's swamp blues. With typical classy eclecticism, Mr McFall's Chamber - the intrepid Edinburgh-based troupe of Scottish Chamber Orchestra musicians and friends - make Beefheart and Zappa the backbone of their latest tour. The programme also showcases first-rate new works by Martin Kershaw and Paul Harrison, both of whom doff their caps to the brash rock iconoclasts but keep their jazz-accented language their own.

There's been a recent explosion of interest in Zappa from the classical music world, with tribute shows at the Proms and Edinburgh. McFall's have been ploughing this field for well over a decade, since early gigs at the original Bongo Club, and their take has a mellow ease to it.

There was laid-back swing in Echidna's Arf (of you) and G-Spot Tornado, Zappa's zany metric shifts lolloping by without much sass or shock factor. The Beefheart numbers (Ice Rose, Suction Prints) could have likewise used more tight-sprung jolt.

But there's a vibrancy in this group's sound that's beguiling. The Habanera from John Adams's Book of Alleged Dances was elegant. Kershaw's Far Vistas translates Caithness scenery to bright, inter-locking percussion against warm padding from strings and French horn. Harrison's electro-acoustic The Dust Blows Forward kicks off with a jaggy, Monk-ish theme; later vibra-phone trills and yearning horn motifs are laced with cheeky keyboard riffs. A recording of Beefheart's grisly singing weaves into the contours of the score: subversive beat-poetry from beyond the grave.