It’s been a long time since Birmingham Contemporary Music Group presented a programme with no “contemporary” music in it.

What we heard on Sunday instead was an enthralling retrospective of what American composers were doing in the early decades of the last century – plus a depressing realisation of the unself-critical material the Australian Percy Grainger was pouring out. His slithery, creepy Free Musics sounded superfluous as soon as they began, and his Random Round (for one of the largest orchestras ever assembled by BCMG, with the welcome inclusion of some Conservatoire students) was just an exercise in extragavant doodling.

That apart, there were many ear-opening wonders in this generous programme conducted by Peter Wiegold, not least the opportunity to savour a first half devoted to largely unknown works by Charles Ives.

Opening with the famous The Unanswered Question (Alan Thomas the appealing solo trumpeter bravely aloft in the gallery), this sequence moved on into a series of short pieces involving various instrumental blocs, and revealing a mystery: had Ives heard all the big-city sophisticated music his scores evoke (Stravinsky and others), or did his imagination conceive and predict so much of what was to come? It was good to hear some of Henry Cowell’s early experiments with a prepared piano and exotic percussion, and to discover the quirky soundworld of Henry Brant, whose Music for a Five & Dime Store was a wonderful sound-picture of violin, vamping piano and tea-room percussion.

And that last idea was brilliantly exploited in John Cage’s cosy Living Room Music. Stars of the evening were the resourceful pianism of Malcolm Wilson, and the stage-management of Peter Harris.