The world of guitar (and synth, and bass…) modulation effects overwhelmed me at first, but I’ve learned that most pedals and plugins are based around just a couple of ideas.
| Time-based effects | Filter-based effects | |
| Base version | Chorus | Phaser |
| Variations | Flange (chorus with feedback) Vibrato (chorus with no dry signal) | Uni-Vibe or “Vibe” (phaser with mis-matched filters) |
Time-based effects are created by 1) copying the input signal, 2) delaying the copy by a small amount (a few milliseconds), 3) automatically changing the delay time (say, from 27 ms to 33 ms and back), and then 4) mixing the input (or “dry,” or “not delayed) and delayed signals together (typically at a 50:50 ratio). The resulting sound is a pseudo-doubling effect with a bit of pitch going up and down, some frequencies of the input signal enhanced, and others diminished. Boom; basic chorus.
Flangers operate on the same principle, with shorter delay times and feedback in the delay signal path (just like a delay or echo pedal), resulting in a more pronounced effect. Flangers with knobs for feedback amount are often great modulation pedals because they can cover a lot of territory from subtle near-chorus to crazy flying saucer flange.
(more…)








