Phaser vs flanger vs chorus: what is the difference?

A phaser creates moving notches with modulated all-pass filters. A flanger mixes the dry signal with a very short modulated delay, creating a moving comb filter. Chorus also uses modulated delayed copies, but typically adds enough delay, detuning and voice variation to suggest several performances.

They belong to the same modulation family, but their spectral patterns and musical impressions differ.

Quick comparison

Effect	Core mechanism	Typical impression	Useful for
Phaser	Modulated all-pass stages mixed with dry	Rounded, sweeping, hollow motion	Pads, guitars, percussion, animated filtering
Flanger	Very short modulated delay mixed with dry	Metallic, jet-like comb sweep	Transitions, drums, guitars, special effects
Chorus	Multiple modulated delayed voices	Width, detuning, ensemble thickness	Vocals, synths, guitars, pads

These are tendencies, not rigid borders. Delay time, feedback, modulation and mix can push one design toward another.

How a phaser works

An all-pass filter can leave magnitude unchanged on its own while shifting phase by different amounts at different frequencies. When that processed path is mixed with the dry signal, some frequencies cancel and create notches.

Several stages produce several notches. Modulating their frequencies moves the pattern. Ableton’s manual describes its Phaser as a series of all-pass filters and its Phaser-Flanger Phaser mode as a phase-shifted path fed back into the input.

Important controls include:

• Stages or poles: number and geometry of notches.
• Rate: modulation speed.
• Depth or amount: sweep range.
• Center: region around which the notches move.
• Feedback: emphasizes the pattern and resonance.
• Stereo phase: offsets movement between channels.
• Mix: balance between dry and processed paths.

How a flanger works

A flanger uses a very short delay whose time is modulated. Mixing that delayed copy with the dry signal creates a comb filter: a sequence of regularly spaced peaks and notches.

As delay time changes, the spacing moves. Feedback reinforces the comb and can produce the classic metallic or jet-plane character.

At very short delay times, small changes create large timbral movement. At longer settings, the effect can approach chorus or doubling.

How chorus works

Chorus creates one or more delayed, modulated copies. The changing delay also creates pitch variation. With suitable timing, voice count and stereo spread, the copies feel less like one comb-filter sweep and more like several slightly different performances.

Core controls include:

• Rate and depth: speed and amount of pitch/time movement.
• Delay: separation from the dry signal.
• Voices: number of simulated performers.
• Spread: stereo distribution.
• Feedback: adds resonance or moves toward flanging.
• Damping or filtering: controls brightness and low-end motion.
• Mix: effect level.

Why the effects overlap

Flanger and chorus both use modulated delay. Their identity depends partly on delay range, voice structure, feedback and mix. A short, feedback-heavy chorus can sound flanged; a longer, gentle flanger can sound chorus-like.

Phasing uses a different mechanism, but deep feedback, distortion and complex stage patterns can create similarly dramatic moving coloration.

Choosing by musical goal

Use phaser when:

• you want movement concentrated in notches rather than obvious doubling;
• the source needs animated tone without a clearly delayed voice;
• sweeping a pad, guitar or hi-hat should become part of the rhythm.

Use flanger when:

• you want a bold metallic sweep;
• a transition needs a rising or falling jet effect;
• feedback resonance should become an audible feature.

Use chorus when:

• a vocal or instrument needs width and ensemble thickness;
• subtle pitch movement should soften a static synth;
• several voices should appear to surround the source.

Stereo width and mono compatibility

Opposing LFO phases and wide voice panning can create impressive headphones width. Mono summing can reduce that effect or expose cancellations.

Check the result in mono and consider filtering modulation out of the deepest low end. Do not assume a wide meter reading guarantees a stable mix.

Placement and gain staging

Before distortion, modulation changes what drives the nonlinear stage. After distortion, it sweeps newly generated harmonics and can sound brighter or more obvious. Before reverb, the moving source enters a shared space; after reverb, the room itself appears to move.

Feedback can raise peaks. Match output level before deciding that a more resonant setting is better.

A fair listening test

1. Use one dry loop.
2. Set each effect to a slow rate.
3. Disable feedback initially.
4. Match output loudness.
5. Compare the movement in stereo and mono.
6. Increase feedback carefully.
7. Choose the effect whose motion supports the arrangement.

SPC Hyper Phase expands the phaser side with dual all-pass lanes, a morphing hyperspace vector, four drawable modulators and custom stage distribution. SPC UV Chorus combines a liquid chorus with frequency-range control, independent dry/wet/artifact colouring and tonal constraints that can follow a key, chord, custom notes or live MIDI.

For more radical transformations, continue with spectral processing and granular synthesis.