We think of glass as something we see, or rather see through, but anyone who has rubbed a finger along a wine glass rim knows the material has promising sonic properties too. Needless to say, these properties are explored in previously unimagined depth and breadth here, in a project conceived by Norway's Terje Isungset – a percussionist and composer more often to be found playing instruments made of ice. Although I've never previously witnessed him playing glass, I've seen his partner in this endeavour, compatriot Arve Henriksen, perform on numerous occasions and in numerous guises, yet he continues to surprise while at the same time – this is the tricky bit – imbuing every note with personality such that he is instantly recognisable as its creator. Together, the glass world they conjure is one of occasional crunches and smashes, but what dominates are haunting, and surprisingly resonant, pitched clunks. Extraordinary.