Six years ago, David Lang won a Pulitzer prize for his Little Match Girl Passion, one of the finest choral achievements of recent times. But it's hard to imagine anything more different from the intricately interwoven lines and poised harmonies of that piece than his latest work for voices. As Lang has revealed, it was when he went to an Arsenal match at the old Highbury stadium that he realised the power a mass of untrained voices can unleash, whether together or in separate groups, and how wide the expressive range of its singing can be. More than 20 years later, that experience has led to Crowd Out, for 1,000 or more voices.

Birmingham Contemporary Music Group, which co-commissioned the piece, organised the first performance in the multi-storey atrium of the city's Millennium Point. Groups of singers, each with their own megaphone-equipped leader, were arrayed on the atrium steps and on different balconies above and around the audience, while conductor Simon Halsey supervised it all from a strategic vantage point, and the entries of the individual groups were cued with coloured flags.

Lang derived his text for the half-hour piece using a search engine to complete the sentence, "When I am in a crowd I …", grouping the results into psychologically distinct collections. The muttering opening begins with "I draw deep breaths" and builds to a massive, multi-stranded climax, while sung phrases infiltrate later sections – there's a simple hymn-like setting of "I feel like rushing into tears", a more elaborate one of "I am obsessed with being at the centre of attention". Elsewhere there are outbursts of applause and derisory shouts, until a final fade-out on a group of phrases that begins "I like people". It's by turns stirring and touching, in the way so much of Lang's best music is.

• Repeated on 21 June at Arnold Circus, London E2, as part of the Spitalfields festival.