A festival of Steve Reich's music at the Barbican in London, happening in September, will be the most lavish British celebration of the composer's 70th birthday this year. But the London Sinfonietta is currently touring its own tribute, taking an all-Reich programme around the major European concert halls. It's a mixture of old pieces and a brand new work: alongside the 1984 Sextet for keyboards and percussion, and the string quartet Different Trains, there's the first performances of Variations for Vibes, Pianos and Strings, which was commissioned for the Sinfonietta and the Akram Khan Dance Company.

Khan's choreography is explosively expressive and wittily integrated into the Sinfonietta's performance, with conductor Brad Lubman taking a role alongside the trio of dancers. To some extent, Reich's score seems to have been designed as a relatively neutral backdrop to all that activity. The instrumental writing in the variations is as beautifully crafted as ever, built upon a rotating sequence of four chords and creating a fast-slow-fast scheme, with the movements getting progressively shorter. But the result is less chromatic and harmonically adventurous than in Reich's last major work, You Are Variations, and seems in many ways to hark back to the world of his 1980s music.

The sextet was also originally commissioned as a dance score, and it shares a family likeness to the new variations, with bowed vibraphone pitches taking on the same function in the harmonic scheme that sustained string notes fulfil in the new piece. It's got more cumulative energy, though, and an architectural sense of closure in this final movement that the new piece, on first hearing, seems to lack.

Alongside those two essentially abstract essay in texture and process, Different Trains seemed as touching and extraordinary an achievement as ever, although some quirk in the otherwise exemplary sound projection made the words of the sampled voices less audible than usual.