"We're like a string quartet, but the most driving and exciting string quartet that you could imagine." Jane Harbour, the violinist of Spiro, is trying to put a neat handle on the essence of this instrumental four-piece. It's not an easy task. Despite the group's folk-friendly tools (violin, acoustic guitar, mandolin and accordion), they're something of a slippery beast when it comes to being contained by mere words. Guitarist Jon Hunt has a go. "We've got more to do with minimalist classical and dance music than we have with folk. Even though we use folk tunes, they're raw materials that the rest of the sound is built around."