In turn, Gastr del Sol directly widened the scope of indie rock, not only folding in jazz players and digital pioneers, but also repeatedly partnering with the minimalist composer Tony Conrad. After helping name the Velvet Underground and working with La Monte Young, Conrad had mostly receded into academia and experimental films. (During the interview, O’Rourke sported the same Conrad T-shirt he wore for Gastr del Sol’s press photos 30 years earlier.) Conrad’s sessions with Gastr del Sol forged a renaissance that lasted until his 2016 death.

“Jim is a tremendous electroacoustic composer, and David is full of sophisticated nuance — impressionistic lyrics, undulating guitar work,” said Jeff Hunt, who linked them with Conrad and released many of their recordings together through his label, Table of the Elements. “They complemented each other like Japanese joinery — no glue, no fasteners, a perfect fit.”

In their fecund Chicago scene, though, they became incredibly busy. O’Rourke played on or produced records by the likes of Smog and U.S. Maple while shaping his own gorgeous solo works, like “Bad Timing” from 1997. Grubbs remained in school, pursuing his doctorate in a start-and-stop process that lasted a decade. Both played in the Red Krayola, a long-running, ever-amorphous collective. Given other commitments, once-complementary roles calcified into strict divisions.

Seams started to show. Resentments grew. Deep fatigue set in. Days before Gastr del Sol began a tour in fall 1997, O’Rourke told Grubbs he was staying home to assemble “Camoufleur,” the first time he’d used the digital editing software Deck II. He’d spend 15 minutes waiting for his Macintosh to render mere seconds of audio.

When they finally finished the album, O’Rourke called to say he quit. Grubbs was less surprised than disappointed, since the glitchy symphonies, vertiginous waltzes and galloping instrumentals on “Camoufleur” suggested they weren’t finished. “That record was a flowering of what we’d done over five years,” Grubbs said, sighing.

But O’Rourke knew there were sounds and situations he craved beyond Gastr del Sol’s boundaries: “I didn’t like my life being constrained by one thing.”