This Eurorack module puts four-part chords and more at your fingertips…
The Chord v2 isn’t just a refresh of Qu-bit’s 4-voice polyphonic harmonizing oscillator that first appeared in 2016. It’s a significant redesign that adds musically useful features in a smaller format and for $100 less than the original. With this module alone, you could make your Eurorack system a polyphonic synthesizer.
The Once Over
Unapologetically digital in sound and design, version 2 of the Chord module has an updated sound engine witheight banks of waveforms instead of one. The factory banks comprise three sets of synthesized tones: Bandlimited Traditional Waveforms, SawTooth through a Low Pass Filter, and Square with Pulse Width Control. It also has five sets of Wavetables: FM, Distorted, Voice, Video Game, and Organ, which has a drawbar vibe. You can select banks manually or with voltage control.
The Waveform selector has a CV input, which opens up a variety of interesting effects when you use a modulator. For example, Bank 2 simulates opening and closing a lowpass filter on a somewhat buzzy timbre when you send an LFO into the Wave input. Throughout the various wavetables, transitions between adjacent waveforms are smoothed over as you move between them. Changing the waveform manually allows you find places where you hear two adjacent waves simultaneously.
Most parameters have a knob with an associated CV input, a combination that allows you to offset the modulation amount. The knobs are also multifunctional, as we will see in a moment.
As with the original module, you’ll find coarse- and fine-tuning controls, individual audio outs for each interval in a 4-part chord— Root, Third, Fifth, Seventh—and a Mix output. Two significant additions are the linear FM input (with attenuator) and the front-panel SD card slot. The card is not only for loading custom waveforms, but it can also store and load a variety of user-defined settings, including chord types, harmonization/quantization parameters, an offset to the Lead input, and a reconfiguration of the memory into a single bank of 64 waveforms. You can also use an SD card to enable LFO mode, which lowers the frequency range of the oscillators by 6 octaves while maintaining the relationship of the outputs following the Mode and harmonization settings (detailed below).
Polyphony à la Mode
The Quality parameter selects chord type—major, minor, dominant 7th, diminished, augmented, and two suspended types (sus4 with a major 7th and sus2 with a minor 7th). My first patch used an LFO to move between a major and minor quality, while my sequencer modulated the waveform at a slightly different tempo to create a jazzy sounding vamp.
Of course, once you’ve chosen a chord, you’ll want to move the notes around for variety. The Voicing control (and its CV input) are used for selecting the chord inversion, such as moving the root note an octave higher so that the 3rd is the lowest note. The Voicing parameter has 17 stages, which are detailed in the user manual.
An additional input jack labeled Lead works in conjunction with the three Mode settings—Melody, Unison Poly Mode, and Free Poly Mode. When the Mode LED is dark, the Lead input is disconnected. In Melody mode, the Seventh output becomes an independent oscillator that is controllable with a CV patched into the Lead input: press the Triad button to limit the Mix output to three voices, and you can use the Seventh to play a melody voice over 3-part chords.
Unison Poly Mode tunes the four oscillators in unison but makes them independently controllable using the various CV inputs. (For example, the V/Oct jack controls the Root tone’s frequency, the Lead input controls the Third’s frequency, and so forth.)
Free Poly Mode gives you full pitch control over each of the four oscillators using the various parameter controls and CV inputs. (For example, Voicing knob and CV jack control the Fifth output’s frequency.)
The Harmonize feature quantizes and harmonizes the inputs based on the selected Mode. In Melody mode (or when no Mode is selected), the V/Oct and Lead inputs can be quantized to major or minor scales, whereas in the two Poly modes, the four inputs can be quantized to major, minor, and chromatic scales. When the harmonization LED is dark, no quantization occurs. You can also disable the feature altogether, so the module behaves like the original model.
While this may seem like a lot to keep track of, Chord v2 is remarkably easy to use. For example, the multicolor LEDs across the top panel indicate parameter choices. To show which bank you’ve chosen, one of the LEDs will flash white for a moment (unless you pick Bank 1, for which the LEDs remain dark).
It wasn’t until I wanted to explore the Poly modes that I had to dig into the manual, and those features only took a moment to figure out. Thankfully, the manual is well written and gives you what you need quickly.
Tomita, Tangerine Dream, and Beyond
In its new incarnation, Chord is still the most convenient and cost-effective way to add polyphony to your Eurorack system, At its most basic, the module offers up sophisticated chordal sequences, reminiscent of ’70s-era synth records, from only one or two inputs.
Yet, Chord v2 is capable of very sophisticated polyphony and timbral modulations when you drive the module from independent sources. In one of my favorite patches, I sequenced various parameters using the 4-channel Stillson Hammer Mk II, as well as various LFOs and VCOs. The results were an ever-changing series of chords and their inversions that, with a little delay, yielded interesting melodic and rhythmic artifacts. With the push of a button, I could instantly change the harmonization.
The linear FM input put the icing on the cake. I used it for a range of effects— from subtle vibrato to variable rhythmic clangor—depending on the rate of the modulation.
Chord v2 adds a wealth of functionality to your Eurorack system. It is definitely worth a listen.
Find out more about the Qu-bit Electronix Chord v2 online at qubitelectronix.com