SHRIEKS -SQUEAKS- SHIMMER : SCIENCE MUSIC

Stuart Hyatt transformed the shrieks and squeaks of bats around him into haunting music.

ON an unseasonably cool evening in late May, Stuart Hyatt emerged from his home in Indianapolis holding a small black box. The moment he stepped outside, the box began to chatter and click.

''Whoa, can you hear that?'' he said, grinning on a FaceTime call.'' I have never seen them fly this low.''

His neighborhood bats had arrived, chasing their nightly meal of insects. And, as usual, Mr. Hyatt was there to listen and marvel, the black box allowing the bats usually inaudible chatter to be heard, even through a cellphone.

Bats have lately been enduring yet another image crisis. Believed to be ancient harbors of coronaviruses, they are reportedly being killed in India and vilified most everywhere for the outbreak.

Over the last two years, though, bats have been Mr. Hyatt's chief musical inspiration.

He has recorded their sounds - so high in frequency that humans typically cannot hear them - and made them audible, then dispatched the material to a team of improvisers and composers, like Kelly Moran, who makes prismatic works for prepared piano, and the drowsy-drone master Jefre CantuLedesma.

''At first the textures and tones seemed chaotic,'' said one of the contributors, Matthew Cooper, who records as Eluvium. ''But you find these bits of melody and rhythm that are so harmonious.''

The result is ''Ultrasonic,'' Mr. Hyatt's eighth album as Field Works. The 14 tracks evoke the mystery of bats' nocturnal escapades, the languor of their hibernation and the existential calamity of the collapse of their habitat.

''Bat noises are like bird songs, just in a register no one can hear,'' Mr. Hyatt said. ''I wanted to bring out the musicality in their voices.''

For Mr. Hyatt, 45, an Indianapolis native, ''Ultrasonic'' is the culmination of a lifetime obsession with sound. His first memory is the sensation of rising from a swimming pool and hearing the world on the other side of the surface.

When he was 3, a family friend suggested a remedy for his hyperactivity ; a tiny violin and the discipline of Suzuki method.

For the next 7 years, the violin was his balm, redirecting his energy and sharpening his focus. But at 10, just as his teacher started explaining musical notation, he decided he knew enough.

''Maybe the violin had done its job?'' he said. ''I was just done.''

But his enthusiasm for sound wasn't. He eventually learned upright bass, keyboard and drums.

The real revelation came when a friend lent him a four track recorder. He'd capture himself singing the same melody in different registers, and also domestic sounds - water rushing from the faucet, for instance, and the rumble it caused in the pipes.

Mr. Hyatt soon realized he no longer cared to hear his own voice; he wanted to immortalize the objects around him.

The World Students Society thanks author Grayson Haver Currin.