Frequency State / Music Production Reference Library · Volume 5
Chorus, flanging and phasing all create movement by combining a signal with altered versions of itself. Their characteristic sweeps come from changing timing or phase relationships over time, but they do not produce identical results.
Chorus: the impression of multiple performers
A chorus effect typically combines the original signal with one or more short, continuously modulated delays. The small variations in timing and pitch can resemble the differences between musicians performing the same part, producing thickness and width.
Chorus often suits clean guitars, pads, electric pianos and sustained synth tones. Too much depth can make a pitched part feel unstable, while extremely wide settings may compromise mono compatibility.
Flanger: moving comb filtering
Flanging uses a very short, modulated delay mixed with the original signal. The overlapping signals create a series of peaks and notches called a comb filter. As the delay time moves, the notches sweep through the spectrum, producing the recognisable jet-like sound.
Feedback can accentuate the sweep, sometimes dramatically. Try it on a drum loop and listen to the cymbal frequencies as the notches pass across them. A mix control allows you to balance the original clarity against the moving effect.
Phaser: shifting frequency-dependent phase
A phaser usually combines the original audio with a version passed through moving all-pass filter stages. These change phase relationships across frequencies, producing notches when the signals recombine. The resulting motion is often described as watery, swirling or hollow.
The number of stages and the modulation range influence the sound. Phasers can be useful on guitars, keyboards, strings and percussion when a gentler movement than flanging is wanted.
Rate, depth, feedback and stereo width
Most modulation effects include a rate control governing how quickly movement occurs and a depth control determining its range. Feedback can accentuate resonances, and stereo modes create different movements in each channel.
Slow modulation may create evolving texture without drawing attention to a cycle. Faster rates may become rhythmic or conspicuous. Tempo synchronisation is useful when the movement should reinforce a groove, but it is not necessary for every ambient or experimental sound.
What changes when you reorder the effects?
A chorus before a distortion processor changes the input spectrum and dynamics of the distortion; chorus after distortion moves the already harmonically rich result. Similarly, placing a flanger before a long reverb can create sweeping echoes, while moving it after reverb sweeps the whole diffuse tail.
The best order depends on whether the movement should belong to the instrument itself or the space surrounding it. Compare the effects at similar perceived loudness so the result is not decided purely by level.
Listening experiment
Choose a sustained sawtooth pad and first add a slow chorus. Notice the widening and pitch movement. Replace it with a flanger and listen for the comb-filter sweep, then replace it with a phaser to hear the different notches and colour.
Keep the original sound and output level similar between tests. Next combine a subtle phaser with a short delay, and listen in mono before deciding whether the added stereo width genuinely helps.
Continue reading
The sources of moving control signals are explained in Modulation (LFO and FM). For spatial context, read Stereo vs Mono, Delay Explained and Reverb Explained.