The Unchambered series, which features ROCO soloists or small ensembles in an intimate setting at MATCH, opens October 6 with “Mind Games.” Premiering a new commission by composer Richard Lavenda, ROCO trumpeter Joe Foley and percussionist Matt McClung react to each other to create the shape of the piece in the moment, and the audience can also join in by voting on their phones to influence the direction of the piece. Joe Foley, trumpet and curator Matt McClung, percussion Bonnie Anderson, piano