Modulation (Chorus, Phaser, Flanger)

Modulation effects change the signal cyclically over time, creating movement, width and shimmer. They share a principle — a slow waveform modulates the sound — but sound distinctly different.

Chorus — Doubles the signal and detunes the copy minimally and wavering. That gives the impression of several slightly diverging guitars — full, shimmering, wide. Formative for many clean sounds of the '80s, but useful far beyond that.

Phaser — Creates wandering cancellations in the frequency band, giving a swirling, "swooshing" shimmer. From subtle-pulsing to overtly psychedelic. Popular in funk, rock and for gentle movement in a clean sound.

Flanger — Related to the phaser but more intense and metallic — a "jet plane" whoosh up to a sharp, resonant sweep. The most striking of the three and the hardest to use subtly.

Prominent references — For chorus, the Boss CE-2 and the Small Clone (the shimmering '80s and grunge clean sound); for phaser, the MXR Phase 90 (the swirling classic) and the Small Stone; for flanger, the MXR Flanger or Boss BF series. Tonal references, not a ranking.

Typical controls — Rate/Speed (tempo of the movement), Depth (intensity), often Mix or Resonance/Feedback.

Modulation is seasoning, not a staple: used sparingly it gives cleans life and leads width; laid on thick it quickly sounds like an '80s cliché. Which of the three fits is purely a matter of taste and style — they solve similar tasks with different character.