Adventures in DIY: Delay Tactics

Creating effects with digital delay
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Mark Isham once told me about the moment he accidentally discovered space. The Grammy-winning composer was preparing to bounce a track when he flipped the monitor switch on his tape recorder too far and heard both the original signal from the record head and the delayed version from the playback head. “All of a sudden, there was that space,” he whispered. “And it changed my life. From that day on, I didn’t use a single synthesizer sound without some sort of time modulation. To me, it just brought that organic, emotional quality that made it seem like night and day.”

I knew what he meant. I had spent a blissful month spinning sounds around my college’s quadraphonic studio with a 4-track tape delay. I routed each track’s playback head to the next track’s record head, then sent each channel to a different speaker. Percussive sounds danced around the room (each speaker an eighth-note behind the previous one), while pads became a tornado of texture. Filter sweeps and pitch bends were especially dramatic, with the modulations swirling through space and time. Connecting multiple delays to multiple speakers is magical.

Fig. 1. Here, I’ve turned a stereo synth into a surround one by running the output through three delays and four speakers.
Fig. 2. The rack delay is set for a quarter-note (500ms) and a dotted quarter (750ms) at 120bpm.

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Looking around my studio today, I was surprised how many digital delays I had; they were inside synths, portable recorders, rackmount gear, stomp boxes, iOS devices, and tabletop effects. To re-create the rhythmic panning effect, I split the output of a synth four ways. Next, I sent one signal to the left front speaker of a multimedia surround system; I sent the second signal through a stompbox delay to the right front speaker; and the third and fourth through a rackmount stereo delay to the right and left rear (see Figure 1). I set each delay to 100% wet, with the stompbox set to 250ms and the stereo delay set to 500ms on the right and 750ms on the left (see Figure 2). Playing at 120 bpm created a whirl of eighth-note echoes.

Next, I mapped a MIDI controller to increase the delay feedback in the rear speakers, adding a cascade of echoes that expanded the space further. You can make this effect even richer by adding more speakers. Because you’re building an acoustic ensemble, any kind of speaker, even small battery-powered ones, will enhance the ambience. Hear a binaural recording of my setup at emusician.com, and let me know what projects you’re making at DIY@batmosphere.com. I’ll cover more DIY surround techniques in a future column.