What Does Chorus Do? Movement, Width and the Sound of the JUNO
Chorus is a modulation effect that can make a sound feel wider, richer and more three-dimensional.
It works by creating slightly delayed copies of the original signal and continually varying their timing and pitch.
When those copies are blended with the dry signal, they create the impression of several performances occurring together.
Hence the name chorus: a group of voices – or, in this case, signals.
In electronic music, chorus is particularly useful for introducing movement and character to sounds that might otherwise feel static, narrow or overly precise.
You can use chorus to:
Widen synths
Add movement to pads, drones and sustained chords
Thicken sampled vocals and backing parts
Add dimension to electric pianos
Turn guitars into wide, atmospheric or digitally animated textures
Animate percussion, hi-hats and drum-machine patterns
Make mono samples feel larger within a stereo production
Seeing Chorus in Motion
The video below uses a 1 kHz sine wave to demonstrate several different chorus designs.
A sine wave makes the effect particularly easy to isolate because there are no additional harmonics or musical details obscuring the modulation.
The goniometer shows how the relationship between the left and right channels changes as each chorus setting is engaged.
Each setting produces a recognisable stereo pattern.
With a lead, pad or complete musical phrase, the display would be more complex, but the underlying movement would still be present.
The first examples use UAD Studio D and Softube Model 84 Chorus.
These effects provide a small number of carefully chosen modes, each with its own character.
Logic Pro’s Chorus takes a more adjustable approach.
Its Rate control sets the speed of the modulation, while Intensity controls how much modulation is applied.
This makes it possible to move gradually between gentle widening, obvious swirling and faster, denser movement.
As Rate increases, the stereo pattern moves more quickly.
Increasing Intensity generally makes the modulation more pronounced.
The important test is still what the effect contributes to the music.
What I Heard
I began this comparison expecting the Dimension D-style chorus to be the main focus.
I regularly reach for UAD Studio D when I want to add width without making the modulation too obvious, and I previously owned a Klark Teknik 3rd Dimension BBD-320, which sounded lovely.
The sine-wave test changed my perspective slightly.
Studio D creates width, but beside Softube’s Model 84 it feels less alive.
Model 84 has a more obvious sense of movement, and its slight instability makes the result feel more organic to me.
That does not necessarily make Studio D less useful.
Its restraint may be exactly what works on a vocal, pad, guitar or complete mix, where obvious pitch movement could become distracting.
A sine wave is excellent for exposing modulation, but it cannot demonstrate every reason an effect might work within a production.
Even so, when the movement is isolated in this way, I find myself much more drawn to the personality of the JUNO-style chorus.
The JUNO Chorus
My first real introduction to chorus came through a JUNO-106 that I borrowed.
The basic synth voice became wider, richer and more animated as soon as the chorus was engaged.
It did not feel like an effect placed at the end of the signal path; it felt like part of the instrument.
That is an important part of the JUNO sound.
The synth is comparatively simple, but the onboard chorus gives it scale and more personality.
Chorus I provides the gentler movement, while Chorus II is faster and more pronounced. Each mode has a strong identity.
The original circuit also introduced a noticeable amount of noise.
Technically, that could be considered an imperfection, but it became part of the instrument’s character.
Modern JUNO-inspired plug-ins often include a noise control because producers may want that texture as well as the modulation.
Softube’s Model 84 Chorus captures the immediate nature of the original design.
More Control with Logic’s Chorus
Logic Pro’s Chorus takes a different approach.
Rather than offering a small number of fixed modes, it provides direct control over the modulation.
This makes Logic’s Chorus far more flexible.
It can create subtle width, slow drifting movement or a much faster and more obvious effect.
As Rate and Intensity increase, the stereo pattern becomes denser and more active.
That range means Logic's Chorus can sit almost anywhere – from Studio D's restraint to Model 84's movement, and everywhere between.
Using Chorus in a Production
Chorus works particularly well on pads, arpeggios, mono leads, sampled chords, vocal fragments and sustained sounds from digital, wavetable or FM synthesisers.
It can soften the precision of software instruments, animate static patches and give narrow or mono sources a greater sense of movement and stereo space.
Used more experimentally, it can also add shifting texture to hi-hats, percussion loops and resampled material.
I would normally keep the kick and deepest bass frequencies stable and centred, as chorus on low frequencies can weaken the centre of a mix.
A useful approach is to begin subtly.
Add enough chorus to create movement, then listen to the sound within the full arrangement.
If you only notice the effect when it is removed, that may be exactly the right amount.
It is also worth checking the result in mono.
Wide chorus settings can introduce phase cancellation, causing parts of the sound to become quieter or thinner when the stereo channels are combined.
If the effect occupies too much space in stereo, try reducing its width or lowering the wet mix. This can retain some of the movement while keeping the sound more focused.
Of course, subtlety is not compulsory.
Push the controls further and chorus becomes a sound-design tool capable of producing dreamy washes, unstable pitch movement and beautifully seasick textures.
Sometimes a sound does not need to be louder or brighter.
It just needs to move.
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