Somewhere in the Groanbox Boys' sound, the jug-band spirit meets the conservatoire - to each end of the musical spectrum's benefit. There isn't actually a jug among the boys' equipment, although Paul Clifford's kitchenware percussion and the "freedom boot" (made from a boot plus bottle tops and souvenirs) surely meet the home-made instrument/back-yard inventiveness requirements.

The Tall Ship on a Sunday evening in May doesn't run to the crickets that enhance the boys' latest recording from Maryland, either. But the down-on-the-farm atmosphere, the "gypsy party colliding with St James Infirmary" vibe and the feeling of being taken on the scariest, most exhilarating train ride are writ large in their live performance.

Banjoist and guitarist Cory Seznec and accordion virtuoso Michael Ward-Bergeman started out as a blues duo - Clifford, along with Ward-Bergeman's fascination with Eastern European folk music, was added later - and their musical understanding during Appalachian ballads and wholehearted blues hollers is almost sibling-like. As Seznec picks with bitter precision, Ward-Bergeman orchestrates with huge chords and punchy basslines. It's a big sound from a small band, but their dynamics go down to a whisper as well as up to a roar.

It's a rich sound, too, with Seznec pulling vintage, deeply characterful tones from guitar and a fretless-sounding gourd-banjo, and Ward-Bergeman adding longing counterpoint as Clifford applies a hammer to a yew log or plays with brushes (as in paint, rather than the standard drummer's issue). All in all, an arresting blend of sophistication, foot-stompin' bonhomie and furious harmonica storms, finishing with the sort of elegantly understated tune that shows why they're starting to get film-soundtrack gigs.