The Manchester International Festival seems to be on a mission to push a number of star names beyond their natural comfort zones; thus we have Damon Albarn producing a Chinese opera, Johnny Vegas trying to sell you a house and now William Orbit - a record producer whose blips and beats revitalised Madonna's career - writing a 70-minute, nine-movement suite for the BBC Philharmonic.

Orbit does have a classical pedigree of sorts. His album Pieces in a Modern Style turned Barber's Adagio for Strings into an unlikely soundtrack for the nation's aerobic classes, and he contributed an ensemble for live musicians and computers to Karlheinz Stockhausen's Elektronic festival at the Barbican in 2001.

Yet he has decided that his debut symphonic work, which goes under the non-committal title Orchestral Suite, should be a purely analogue affair. It is a bold move, yet also slightly bizarre as it completely abnegates his unique compositional voice.

As a producer, Orbit's chief ability is to stamp his sonic imprint on things, yet the most immediately apparent aspect of Orchestral Suite is that it does not sound like Orbit at all. There are some repetitive, minimalist figures, lots of lazily ambient strings and a female chamber choir periodically required to open their mouths and say "ah". You could interpret this as an extension of the sublime Strange Cargo albums, yet whereas Orbit is capable of making computers sound like angels hallucinating, he makes an orchestra sound pretty much like an orchestra.

There is no reason why a leading artist in one field should not have the freedom to experiment in another - just mildly surprising that, removed from the mixing desk, the sounds in Orbit's head turn out to be so conventional.