Mod Squad: 4MS Dual Looping Delay

From Frippin' to rippin' in 20HP
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The result of a collaboration between 4ms and Gary Hall (designer of the Lexicon PCM42 in the early ’80s), the Dual Looping Delay (DLD) is specifically designed for musicians who capture and manipulate audio loops in real time, whether onstage or in the studio. In addition to providing 2 minutes and 54 seconds of loop time per channel at 16 bits (half that amount of time at 24 bits with Version 5 firmware), the DLD’s CV I/O adds extensive modulation capabilities that Eurorack users expect.

The module can handle audio input frequencies up to 24 kHz, and internal digital processing is done with 24-bit, 48kHz resolution. DC coupling of each audio input is also an option.

The module can be configured in several ways: two mono channels, mono-in/stereo-out, single-and dual-input cascading delays, or sound-on-sound-style. Both channels have their own Mix control, as well as an insert for processing the delays, and a knob and CV inputs for Feedback and Delay Feed. You can select the Reverse or Hold modes for each channel manually or with a trigger.

Though each channel has independent audio I/O, both channels follow the same clock—called Ping—which you can set tap-tempo-style or with an external signal. Nonetheless, you can make the channels sound as coordinated or disconnected as you like. Outputs for the clock and time divisions are available and can be patched back into the DLD or used to control external modules.

The division or multiplication of the clock for each channel is set via its Time knob and division switch. From there, you can add modulation from the Time CV inputs. As a result, the DLD can go from resonant Karplus-Strong timbres (tunable via CV) to evolving delays nearly three minutes long. You can even do “windowing” and “granular scrubbing” to move within sections of a loop.

One of my favorite DLD patches was designed to create Frippertronic-style effects: Using the outputs from a Tom Oberheim TVS-Pro, I exploited the full delay length of each channel to build sustained chords, which were hard panned to each speaker for pseudo stereo effects. Later, I cross-patched the clock signals to introduce rhythmic variety and add stuttering within the stereo field.

Synchronizing the module from an external clock is fun and inspiring. I patched a gate signal from the TVS-Pro’s sequencer to the DLD’s Ping input and dialed in polyrhythmic divisions for each delay to enhance and extend the sequenced pattern. Patching Loop A’s clock output to the Time B input, and vice versa, delay rhythms could be intensified as I improvised with the Time controls and simulated out-of-control tape-delay buildup with the Feedback knob.

As a basic delay and looper, the DLD is surprisingly easy to use given its deep functionality. But expect to invest some time with the module to fully understand its capabilities. In that sense, the DLD could be considered a work in progress, in a good way: Most new features (such as 24-bit audio quality), added via simple firmware updates, are musically useful and based on user feedback.

At $415, the DLD is no impulse buy. But if you crave extensive looping and modulation in a Eurorack environment, the Dual Looping Delay's broad feature set and excellent sound quality will more than satisfy