Bandleader Tony Haynes has a mission to bring the peoples of the world together, and there were times during Where The Rivers Meet when it looked as if they were all trying to squeeze into Sadler's Wells in person. This cross-cultural spectacular involves the big band-sized Grand Union Orchestra, plus singers and players from China, Bangladesh, Turkey and Chile, a choir, children playing steel-pans, student jazzers and more.

It's the kind of thing that sounds fantastic on paper. It often looks and sounds pretty good on stage too, though with some longueurs and structural incoherence. Over three decades, Haynes has been a tireless worker for community music, and he has used Grand Union and its predecessor Red Brass as the jazzy professional core of many bold projects involving youth bands, amateurs, and folkloric groups of all kinds.

But the snag he still wrestles with is that the concept sometimes outpaces the music for substance, vision and surprise. Where the Rivers Meet embraces themes ranging from western exploitation of Africa to traditional songs of Asian fishermen and Chilean exile laments. The jazz musicians supply rich orchestral support, and the soloists interject an invigorating energy, trumpeter Claude Deppa and saxophonist Tony Kofi particularly. When the chemistry ignites - like singer Brenda Rattray's majestic voyage over a slow funk groove, or the orchestra sounding as plaintively sonorous as a brass band behind resonating Turkish melodies - it lights a flare over the project's potential.

But the eloquence of music springs from inside, not from an imposed programme. Maybe Haynes, an inspired enabler, might now go the extra mile to draw a wider spread of composers into this big picture. Then the musical impact might more closely match the glowing ambitions of the founding idea.