Who'd have thought about basing an album on the sound of beating cloth on a table? Capercaillie, that's who.

Don't get me wrong, Sidewaulk isn't a recording of wool slapping wood. But the Scottish semi-traditional band drew upon Orain Luaidhaidh, or "waulking songs," for inspiration for the album. Waulking songs, the band explains in the liner notes, were sung to accompany the rhythm of beating cloth on a table, a method for shrinking tweed or blanket cloth after it was taken from the loom. The first track on the album, "Alasdair Mhic Cholla Ghasda (Alasdair, Son of Gallant Coll)," is a foot-tapping call-and-response waulking song from the island of Barra which shines a strong spotlight on Karen Matheson's vocal strength as well as the band's tight and lively playing.

Capercaillie, in the years since Sidewaulk was released, has achieved a certain degree of fame, largely due to the gorgeous voice of lead singer Matheson (who was featured in the soundtrack of the movie Rob Roy and appeared briefly in the film to sing besides the clan gathering's fire). Matheson's voice is strong and sweet, perfectly suited to the material chosen by the band -- from the lively, vocally rhythmic "Alasdair Mhic Cholla Ghasda" and the danceable mouth music of "Fosgail an Dorus/Nighean Bhuidh' Ruadh (Open the Door/Russet-Haired Daughter)" to the lovely Barra ballad "Iain Ghlinn' Cuauch (John of Glen Cuaich)" and the melancholy "Fisherman's Dream." (Except for "Fisherman's Dream" and the proud Dick Gaughan ballad "Both Sides of the Tweed," all tunes on this album are sung in Gaelic.) "Oh Mo Dhuthaich (Oh My Country)" ends the album with a mournful emigrant song, powerfully sung by Matheson and backer Manus Lunny, accompanied only by Donald Shaw on a sonorus electric keyboard.

It's hard to choose favorites between Capercaillie's fast-paced songs and slow ballands -- Matheson handles both styles with amazing aplomb. But Capercaillie doesn't give short shrift to Scotland's instrumental roots, either. The lively "Sidewaulk Reels" would get any ceili crowd hopping, as would "The Turnpike" set, rocky "Ballindore" and "The Weasel."

Although the band in 1989 was strongly rooted in Scottish musical traditions, the members weren't shy about stretching the limits with notably nontraditional arrangements. Charlie McKerron, for instance, would do any traditional fiddler proud with his deft stylings, and Marc Duff's whistles, recorder and bodhran would are equally excellent. Duff steps past the bounds of tradition with a wind synthesizer, however ... but I would be lying to say it doesn't fit into the Capercaillie sound without a hitch.

Irishman Lunny provides the bouzouki and guitar with his usually excellence, as well as a few backing vocals. John Saich also sings backup and plays guitar and bass for the band. Shaw rounds up the list with accordion and keyboards.

Together, they play with confidence and inarguable skill. Capercaillie could easily survive as a vocal-oriented or instrumental band; with Sidewaulk, they've found the perfect balance. Likewise, they could make their mark as a traditional lineup, but the modern touches give Capercaillie an identity all its own.