Duke Performances wound up another amazing semester of events with the John Hollenbeck Large Ensemble, “featuring” vocalists Theo Bleckmann and Kate McGarry. It was a brilliant programming decision, following as it did on the previous night’s concert, in which Lost in the Trees played with a chamber orchestra. Those string-heavy sounds still so fresh in the mind’s ear, it was possible to really examine the differences in impact when the ensemble is primarily brass and woodwinds.

Hollenbeck, an almost incredibly prolific and varied musician, centers the Ensemble on drums, the ranks of players fanning out around him. Although he’s setting the beat, the Ensemble is conducted, by JC Sandford. Hollenbeck just sits in the middle, looking harmless and mild-mannered. But he’s really an intergalactic music explorer, taking new compositions and old standards for long crazy rides through asteroid belts and variation zones, before returning them, only slightly mussed, to their home melodies. Behind him mallet percussionist Patricia Franceshy puts on a mesmerizing show, at times bowing the resonators of her vibraphone to create unearthly waves of sound; at other times briskly employing four mallets on the bars. The vibe sounds, together with the bass notes from Martin Wind, Matt Mitchell’s piano cascades, and Hollenbeck’s steady sharp rapping and clicking, would have made a full meal of music — just the rhythm section alone. But beyond them soared and wailed rows of saxophones and other woodwinds, trumpets and trombones — up to 13 at a time.

It’s a rich sound, jazzy (though without swing), and loud, and I waited anxiously to learn how the singers would work with it. At last Theo Beckmann came on stage and began to sing. At least, he looked like he was singing. His mouth moved, and his throat… but his voice was just one more instrument in the heady blend: it could barely be distinguished. He seemed to have his microphone level controls to hand, and increased and decreased the volume, so that occasionally lyrics could be heard. I found this terribly frustrating. When Kate McGarry joined him, they sang one song together in which it was possible to hear their silky voices, hear their phrasing and intonations — which made the rest even more maddening. I’ll be puzzling over this baffling use of singers for a long time to come, but the bowed vibraphone almost compensated for the lost voices.