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Alasdair Fraser has spoken often about the fiddle and cello partnership he's established with Montreal-based Natalie Haas being a throwback to 18th-century Scotland. But it's also a super-vibrant contemporary vehicle for tunes written in the various traditional styles and is gaining a repertoire, some of it drawn from the spirit if not necessarily the musical essence of geographically further-flung sources, all the time.

Over two sets that seemed to pass quicker than the clock claimed, they acknowledged the strength of recent Scottish compositions such as Duncan Chisholm's lovely, gently melodious The Farley Bridge, as well as introducing the notion of a new dance for 2014, the referendum shuffle, and grooved over the sea to Mali and Burkina Faso with the Wagadugu Boogie.

As many gigs as they must have played together over the past decade or so, there remains a striking spontaneity about Fraser and Haas's music-making. He has tonal variation and attack to spare, but what makes them so consistently absorbing is the responsiveness each shows to the other. Haas is more than a cellist: she's the rhythm section who uses the percussive chip'n'chop of her bowing and the double bass-like pulse of her pizzicato playing to great effect. The accompanist's role moves so fluently between them, building tension all the while, and then they'll slip into unison and it's like floodgates opening. There was a particularly fine example of this on another newer piece, a suite linking jig, reel, waltz, strathspey and possibly other dance measures, that could easily have sounded bitty, but didn't so much flow as sing all the way to the coda.