There's dance to music, there's dance with music, and - much more rarely - there's dance as music. In Finding Synaesthesia, a Canadian collaboration between tap dancer Heather Cornell and composer Andy Milne, tap dance works almost like a member of the band.

The show opens in darkness, so that the stage is filled only with the soft rattle of Cornell's steps. Gradually, the lights go up, and she is joined by cellist Rufus Cappadocia, vocalist Malika Zarra and Milne on piano. Rebecca Birch's unintrusive video projections also focus on music: closeups of piano strings, the shadow of a tapping foot.

Musically, Milne harnesses a wide and unexpected range of sounds and influences; it's remarkable that the result is never hotch-potch. There are lush Gershwin chords, wonky Thelonious Monk basslines, mystic harmonies reminiscent of Satie. Zarra is captivating, with a soft voice and a hushed style of scat-singing that makes her sound as if she is casting spells. One number, with its regular piano chug, feels like a ride through shifting aural landscapes. Indeed, with its chilled attitude and hypnotic vibe, the whole experience is quite trippy.

As music, the tap dance works within the musical texture, splashing through puddles of piano notes, or scuffing against the block chords like sandpaper. As dance, though, it is curiously self-effacing. Cornell is joined by two British guest dancers, Jess Murray and Junior Laniyan, but there is little of choreographic interest between them. The laid-back style is all in the feet, with arms, torso and face responding passively.

Intricate as the steps are, the result becomes unexpectedly monotonous: the arcane pleasures of rhythm and improvisation belong more to the dancers than to us.