For most of this month, visitors to the Museum of Contemporary Art have been greeted by a low drone coming from somewhere north of the building’s main hall. If it happened to be a Tuesday evening or a Saturday afternoon, they might’ve heard other noises—drumming, snippets of narration, fingerpicked electric guitar—weaving in and out of that drone. And if they followed the sound to its source in the McCormick Tribune Gallery—on the main floor, near the spiral staircase—they might’ve found one or more musicians performing to an audience of a few dozen.

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Northwestern law student Matt Clark and sound engineer Jeremy Lemos have been playing together as White/Light since 2004, creating transcendentally loud and densely psychedelic drone-based instrumental improvisations. In early 2007 they performed at an MCA exhibit by Terence Hannum (who’s half the Chicago drone duo Locrian), and soon they got to talking with the museum’s curatorial staff, who’d liked their music, about a project of their own. Their MCA installation, Untitled, which opened March 6 and closes this Sunday, arose from a concept they came up with about two years ago.

“It was insane,” Lemos adds. “It would have cost $10,000 . . . “

Though visitors commonly lean into the microphone to talk or sing, says Clark, it doesn’t actually work. He calls it the “cheese in the mousetrap”—the idea is to lure people into the path of the beam so they’ll interact with the music. Breaking the beam activates a ring-modulator pedal that modifies one of the 14 tracks.

On Tuesday, March 16, John McEntire of Tortoise and the Sea and Cake accompanied Untitled with a fanciful rig that included a Buchla modular synth, a Suzuki Omnichord, and something called a Luminist Garden—a flat wooden box whose copper top bristles with plantlike clumps of clipped guitar strings maybe four or five inches high. When McEntire stroked or tapped them, they produced strange, alien rattling noises. His other gear created electronic beeps, clicks, and whirrs that chased one another around the room, flitting from amp to amp. His contributions lifted the drone up and made it seem to dance.

White/Light Sun 3/28, 3 PM, Museum of Contemporary Art, 220 E. Chicago, 312-280-2660, free with museum admission.