On their fifth release in six years, this outgoing Celtic band transcend their folky roots with help from Grammy-winning producer Neil Dorfsman. Seamus Eagan’s elegant yet soulful fiddle playing remains center stage, but around it this trad ensemble’s arrangements move in many new directions. Their cover of Tom Waits’s "Darkness Darkness" offers a funkified take on Celtic pop that equals and maybe even surpasses anything Afro Celt Sound System have come up with. And though their interpretation of Nick Drake’s "Clothes of Sand" begins as a mournful ballad, as it ends, the graceful melody floats into a churning current of energized rhythm.

Deirdre Scanlan’s fresh, clean, airy voice is almost too pretty for the spare, dark rocker "Poison Jester" and for the disc’s gushing cover of Bob Dylan’s "Dignity." But it’s just right on "Black Annis," a moody meditation on sexual abuse based on a Scottish folk tune, and on the graceful reading of another Waits tune, "Georgia Lee," which closes the album. There are also the expected instrumental fireworks from Eagan, who’s given plenty of room to stretch out on violin: "Charmy Chaplin" builds off a merry, jig-like melody, "Beck Street" delivers a driving, polyrhythmic jaunt. Inviting Dorftsman’s input was an adventurous strategy, and one that leads to tasteful arrangements, great playing, and surprising departures that separate Solas from the Celtic pack.

(Solas perform at Sanders Theatre on Friday March 15. Call 617-876-4275.)