“The whole feel of the DL4 was, ‘This needs to not feel like a digital product,’” Tripps said. “Does it bake your cookies for you? No. It’s giving you a whole lot of sound, but it’s working pretty traditionally.” Simply put, the DL4 was a digital delay that behaved with the ease of a classic analog device, making it a go-to device in a transitioning time.

Since the DL4 is used most often in these contexts to lasso and manipulate sound rather than to produce it, you don’t necessarily “hear” the pedal on every record it appears. But the Big Green Monster, as it’s sometimes referred to, is quite easy to spot onstage. It’s nearly a foot wide with four stompbox switches, and it’s painted deep, metallic green. There’s a mode switch knob, to change between different styles of delays, and five mod knobs, that change the speed, timbre, length, and tone of those delays. But for the loop function—without question the most influential aspect of the pedal—those four knobs are fairly intuitive, especially compared to other loop pedals at the time, with their LED screens, memory banks, quantizers, and beat-matching functions. The DL4 was simple: hit one button to record, hit it again to stop recording. Another button could play the loop in halftime, a third button could play the loop from the beginning. The fourth switch simply stopped recording.

“The simplicity of what we chose is what ended up being attractive, because making real-time music is a right-brain activity,” said Marcus Ryle, the CEO of Line 6 and one of the pedal’s engineers. “It’s a fully creative activity. And when products get too complex, you suddenly have to be left brain and analytical to run them. Just having four buttons and a handful of knobs, people just got to where it was purely subconscious and second nature how to operate it.”

The DL4 first entered many artists’ arsenals because it could recreate so many different sounds, an effect that previously had been pricey to achieve. In fact, the loop function initially was seen as secondary to the multitude of delays—almost a bonus of the device. Musician, beatboxer, and comedian Reggie Watts started using the pedal when it first came out because he wanted to mimic a Roland Space Echo, a tape delay effects unit from the 1970s that wouldn’t travel as well on tour. But it was the DL4’s loop function that would eventually dominate Watts’ oeuvre: He often uses several of them in tandem to layer vocal beats and singing. “And I don’t use the other modes at all,” Watts added.

A similar story is true for Dave Knudson, guitarist of the math-y indie rockers Minus the Bear. “I was only using it for delay, and then at some point I was like, ‘Let’s see what this looper thing is.’ From there, it just went deeper and deeper. It’s been a point of inspiration for me for a long time and even to this day.” Revered by guitarists for his double-handed tapping technique, Knudson has been known to use as many as four DL4 pedals at a time now. But the clipped fingerprint of the DL4 loop first emerged in Minus the Bear’s catalog on “The Game Needed Me,” the opening track from the Seattle band’s second LP, 2005’s Menos El Oso. “When we were writing Menos El Oso, I was really into Four Tet, Caribou, DJ Shadow, Amon Tobin, kind of sampled, cut-up sounds,” Knudson said. “I was trying to figure out a way to replicate that and the DL4 did it.”

What you can hear on that record, and so many others, is how the DL4 became an indispensable composition tool. Not only can you loop a sound, but you can put that sound in halftime, in reverse, or trigger only a part of the loop. It also doesn’t bend the loops to any quantized grid, meaning “computerized” sounds could be played in human ways.