He assumed the universal posture for how-do-I-get-out-of-this-mess: he leaned forward, rested his elbows on his knees, clasped his hands together and solemnly looked at the floor.
Otomo Yoshihide performed with two guitars, two amps and some objects. His feet rested on two volume pedals for the guitars, both in the up position for no volume. Very gradually, so that you could hear the change but hardly see it, he pressed down on the pedals, until the guitars were feeding back. He used only his amplifiers, not the house system, but the sound fully inhabited the room.
This was on Friday night at Miller Theater, in a concert called “Listening In, Feeding Back”; it presented two compositions and one improvisation, all related to feedback. Mr. Otomo’s “Modulation With 2 Electric Guitars and 2 Amplifiers” was written in 2006. He’s better known for using electronics and turntables, but is generally interested in putting instruments to uses other than their original purpose.
At the peak of his piece, sound waves from the amplifiers started talking to one another: the feedback became autonomous and self-directing, with whistling darts of high- frequency sound and gathering whines of deep hum. (The two guitars had different sonic personalities: one had a semihollow body, the other a fully hollow body.)
For about 15 minutes in the middle, he moved things on and off the guitar strings: alligator clips, finger cymbals, a capo. With each object, a new door opened in the texture of the sound or a new key emerged. At its loudest, the sound pushed against your head, but it didn’t cause discomfort. Mr. Otomo found a balance between disciplining the sound and letting it be unruly.
