After 21 years together, Lúnasa's wheels are still spinning, taking them to pastures new. Cas (turn) is an apt title for an album that sees them include guest vocalists for the first time.

They also have a new guitarist, Ed Boyd (formerly with Flook). Natalie Merchant, Eric Bibb, Mary Chapin Carpenter, Tim O'Brien and Daoirí Farrell make for a wide and somewhat disparate mix, with Merchant's reading of The Bonny Light Horseman proving the most organic. But it's a struggle to find coherence in the band's choice of Paddy's Green Shamrock Shore for Daoirí Farrell and My Lord What a Morning for Eric Bibb.

In truth, it's in the tunes that the band shines most brightly, as they always have. Piper Cillian Vallely contributes three original tunes, each of which is a sinuous delight, and the tune set Sinead Máire's is complemented by the flawless pairing of low whistles and flute: a signature Lúnasa sound.

A venture that may well expand their reach (to song lovers), but the real magic of this collection rests deep within the band's exceptional tune choices, ever-inventive arrangements and immaculate playing. lunasa.ie