Bard College’s new Frank Gehry-designed 900-seat adaptable auditorium “is an inviting and intimate place to hear music. The simple décor is handsome, with smooth concrete walls, wood-paneled balconies and a soft-hued wooden proscenium (retractable to accommodate the staging of opera and theater works). On first hearing, it’s hard to assess fully the work of the acoustician, Yasuhisa Toyota.