Daniel Dehaan

Audio Effects — Explained

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Audio effects come in a million different flavors, but everything they can do to a sound comes down to altering one of three things: its volume (amplitude), its frequency (pitch and tone), or its time (when, and how many times, we hear it). Sorting effects by which of the three they touch makes an unfamiliar plugin easy to place, and it makes the sound of each family easier to learn.

Each effect below has its own page with a plain-language explanation, a demonstration, and a free plugin to try it with.

Seeing and Hearing What an Effect Does

Amplitude-Based Effects

Sometimes referred to as dynamics processors (dynamics being another word for the amplitude range or character of a sound), amplitude-based effects achieve their results by manipulating the volume of a sound — the whole signal, part of its range, or, in the case of filters and EQ, the volume of particular frequencies.

  • Amplitude Modulation (AM / Tremolo) — modulate one signal’s volume with another; below ~20 Hz you hear tremolo, above it new tones appear
  • Ring Modulation (RM) — like AM, but the original tone disappears and only the sum and difference tones remain
  • Compression — reduce the distance between the loudest and quietest parts of a sound
  • De-Esser — a compressor that only acts on the high frequencies, for sibilance
  • Expander — the opposite of a compressor: makes quiet sounds quieter
  • Gate — how quiet a sound has to be before it is turned off entirely
  • Limiter — a ceiling: how loud a sound is allowed to get, no exceptions
  • Transient Shaper — a quicker way to sharpen or soften attacks than a compressor or expander
  • Distortion & Saturation — drive a signal until whatever it passes through overloads, from warmth to wreckage
  • Filters — the tool before EQ; reach for one to add color, warmth, or movement
  • Equalizers (EQ) — shape the tone of a sound by adjusting the volume of specific frequency ranges

Frequency-Based Effects

These effects change the pitch or frequency content of a sound directly rather than its level.

  • Chorus — blend a sound with a slightly delayed, slightly detuned copy of itself, like a choir singing one melody
  • Frequency / Pitch Shifter — move every frequency in a sound up or down, musically (pitch) or by a fixed amount (frequency)
  • Autotune — pull a sung or played pitch toward the nearest note of a scale

Time-Based Effects

These effects work by delaying copies of the sound and combining them with the original — from a single echo to thousands of reflections.

  • Delay / Echo — one or more discrete, audible repeats
  • Phaser — sweep notches through the sound’s spectrum with an all-pass filter, for a swirling motion
  • Flanger — a very short, modulated delay mixed with the original, for a jet-engine sweep
  • Reverb — the sound of a space: thousands of reflections that blur into a tail