Mod Squad: Chord Instant

4-Voice polyphony and a whole lot more
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Assembling a polyphonic modular synth can be expensive, but QU-Bit has an elegant, cost-effective solution. The Chord ($399) is an oscillator that creates 3-and 4-voice diatonic chords, and automatically harmonizes them based on CV input from a keyboard, sequencer, or other source. The module is simple to use: There are no hidden menus or multiple button presses to remember. All of the features are at the top level. And you don’t need to know any music theory to get very sophisticated results.

The Chord provides individual outputs for each chord tone—root, 3rd, 5th, and 7th—as well as a summed Mix output. Each jack delivers a 10V peak-to-peak signal. To hear 3-note chords (root, 3rd, and 5th only), press the Triad button. This limits the output to basic major, minor, and diminished chords (and their modal counterparts) without the added 7th.

Overall tuning is set using the Coarse and Fine knobs in conjunction with the 0-5V input, which determines the root pitch of a chord. The Coarse control covers about a four-octave range when no CV input is present, whereas the overall range of the oscillators seems to be about six octaves, depending on the note spread and inversion.

Each of the four parameters in the lower half of the module has a dedicated trim control and 0-5V CV input for modulation. The Waveform CV input is used to morph between the module’s four basic wave shapes: sine, triangle, ramp, and square. The waves sound digital and organ-like, and the square wave, in particular, can be a bit brash. (I heard occasional aliasing artifacts in the upper registers when the voices were isolated). Nonetheless, there’s a certain cheerfulness to the sound of the voices because of their identical timbre and the solidity of the tuning.

The Voicing control and CV input set the distances between chordal tones, starting with a close harmony and extending to three octave displacements. The Inversion parameter determines the lowest note in the chord—from root position through third inversion when you are using 4-note chords: When the Triad button is engaged, the third-inversion setting gives you a root-position chord an octave higher. The Quality knob and CV input are used for selecting major, minor, or diminished chords when Triad is engaged, or any of the four 7th chords when you’re in 4-voice mode.

An especially welcome feature in this module is its Harmonize mode. The CV input is used as the bass note around which the module creates modal and diatonic harmonies based on a major scale. Modulating the Voicing and Inversion parameters while using Harmonize yields very musical chord progressions with very little effort. The module saves your most recent Harmonize settings when you power down.

On its own, the Chord is very satisfying to use, but the module really comes to life when paired with filters and delays. For example, I used the four sections of the Koma Elektronik Komplex Sequencer to coordinate the modulation inputs of the Chord with those on a resonant filter and a pair of delay modules to create some wicked Tomita-esque soundscapes that slowly shifted and evolved over time.

Although the Chord is a fairly specialized module, it is a lot of fun to use, even in non-tonal settings when bathed in distortion. But if you’re looking to add traditional chordal sounds to your patches, this is definitely the go-to module.