Steve Reich's influence has always spun in all directions, but even he must have surprised himself here: rock-band instruments playing in riffs and grooves with the notated precision of classical chamber music. Double Sextet uses Grammy-winning ensemble eighth blackbird's cool combination of flute, clarinet, vibraphone, piano, violin and cello doubles. 2x5 from Bang on a Can, premiered at the Manchester festival, employs electric and bass guitars, piano and drum set. These two small groups double their numbers by playing against recordings of themselves, though instruments alone can be used. But this is music, not a game of numbers. It's fresh, hypnotic and beguiling and shows the American Reich on a new curve of invention.