A phaser is a human-made audio effect technique that mixes a dry signal with a phase-shifted version of itself, producing a sweeping comb-filter 'swoosh' sound. Mechanism: the input signal is split into two paths — one remains dry, the other passes through a cascade of all-pass filters whose phase response creates frequency-dependent delays; the two signals are then summed, producing constructive and destructive interference (comb filtering). An LFO modulates the all-pass filter parameters, sweeping the notches through the spectrum. The result is a characteristic sweeping, swooshing sound. Parameters: (1) number of all-pass stages (typically 2–12; more stages yield deeper notches); (2) LFO rate (typically 0.01–10 Hz); (3) LFO waveform (sine, triangle, or random); (4) feedback (amount of output fed back into the all-pass chain, intensifying the notches); (5) wet/dry mix ratio. Persistence mechanism: the technique is fixed by its algorithmic recipe (all-pass filter cascade with LFO modulation, wet/dry summation) and persists as hardware guitar pedals, DSP plugins, and built-in patches on synthesizers and multi-effects units. [formal: phasor | substrate: behavior | horizon: a moment | explicit: yes | epoch: 0.01]
Accepted ontology entry
phaser
A phaser is a human-made audio effect technique that mixes a dry signal with a phase-shifted version of itself, producing a sweeping comb-filter 'swoosh' sound. Mechanism: the input signal is split into two paths — one remains dry, the oth…
Definition
Why it is in scope
A human-made audio effect technique: mixing a signal with a phase-shifted version created by all-pass filter cascades to produce a sweeping comb-filter 'swoosh.' Built to persist as a standard effect in guitar pedals, DSP code, and studio processing.
Names and aliases
- phaseren · CANONICAL
Relations from this entry
- all-pass-filterDEPENDS_ON →
Removal test (Law 8): a phaser cannot operate without all-pass filters — the entire mechanism IS the phase-shifted signal path created by all-pass filter cascades. Remove the all-pass-filter construct and the phaser has no working mechanism. The edge tests object-level operation, not sayability (Law 8b). Direction: phaser (dependent) -> all-pass-filter (dependency).
- audio-effectINSTANCE_OF →
A phaser is a specific kind of audio effect: it intentionally alters a sound by mixing a signal with its phase-shifted self through all-pass filters to produce a sweeping comb-filter 'swoosh.' Nearest kind is audio-effect (Law 11e). Direction: specific (phaser) -> general (audio-effect).
- lfoDEPENDS_ON →
Removal test (Laws 8a/8b): the phaser definition states 'An LFO modulates the all-pass filter parameters, sweeping the notches through the spectrum.' Without the LFO, the phaser reduces to a static all-pass phase-shift — no sweeping, no comb-filter swoosh. The LFO is constitutive to the phaser's operation, not optional. Pinned sense: LFO as the modulator driving the phaser's time-varying notches. Direction: phaser (dependent) → lfo (dependency).
- delay-lineDEPENDS_ON →
A phaser operates by routing signal through a series of all-pass filters that introduce frequency-dependent phase shifts. All-pass filters in audio are implemented using delay-line structures. Remove the delay-line — all-pass filtering cannot function — and the phaser mechanism ceases to operate. The dependency is constitutive: delay-lines are the substrate mechanism enabling the phase-shifting that defines phasing.
- cmsp49ekv0413jlssad11emypDEPENDS_ON →
A phaser works by splitting the signal, passing one path through a cascade of all-pass filters (which are frequency-dependent phase-shift filters), and mixing it back with the dry signal. The interference between the phase-shifted and dry paths creates the characteristic swept notches. Remove filters and the phaser's mechanism vanishes — it cannot operate. Passes Law 8 removal test.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Sep 6, 2026, 9:14 PM UTC
- Content hash
- 175a79acfea9791ceb44a67040ffdce611faa4c896f47d5fc1bd626bb1aeea5b