SAMPLED

Synthesis and sound design · updated 2026-08-16

LFO

Low-frequency oscillator: a slow wave used as modulation rather than sound. Vibrato, tremolo and wobble bass all start here.

Close-up of a Eurorack modular synthesizer: oscillator, filter and envelope modules wired together with patch cables, showing the signal path these synthesis terms describe.
Synthesis and sound design — Close-up of a Eurorack modular synthesizer: oscillator, filter and envelope modules wired together with patch cables, showing the signal path these synthesis terms describe.

Photo: Eurorack Modular Synthesizer Closeup (opens in a new tab) by Nir Yaniv (opens in a new tab), via Wikimedia Commons — CC BY-SA 4.0 (opens in a new tab)

Key takeaways

  • Low-frequency oscillator: a slow wave used as modulation rather than sound.
  • Vibrato, tremolo and wobble bass all start here.
  • Routed to pitch it gives vibrato, to amplitude tremolo, to filter cutoff a sweep, and to pulse width the classic thickening motion of vintage string machines.
  • Sync an LFO to a dotted eighth on filter cutoff for movement that stays locked to the arrangement.
  • Watch out: leaving every LFO free-running.

Quick checklist

  • Can you define lfo in one sentence without looking?
  • Can you point at lfo in a real session, mix or contract?
  • Have you tried the practical move above at least once?
  • Would you catch the common mistake before it costs you a take?
  • Have you opened one of the primary sources below rather than a forum thread?

LFO IN DEPTH

A low-frequency oscillator modulates parameters below the audible range. Routed to pitch it gives vibrato, to amplitude tremolo, to filter cutoff a sweep, and to pulse width the classic thickening motion of vintage string machines.

How it works in practice

Sync an LFO to a dotted eighth on filter cutoff for movement that stays locked to the arrangement.

The mistake people make

Leaving every LFO free-running. Unsynced modulation on multiple layers makes the patch feel unsteady rather than organic.

WHERE LFO SITS

LFO belongs to synthesis and sound design in the Sampled music glossary. How synths make sound, in the order the signal actually travels.

TERMS THAT DEPEND ON LFO

  • Modulation matrix

    A routing grid that connects sources (LFOs, envelopes, velocity) to destinations (cutoff, pitch, pan) with an amount for each.

TEST YOURSELF

0/3 answered · 0 correct

3 quick questions on lfo. Answers are marked instantly — nothing is sent anywhere.

  1. 1. Which statement best describes lfo?

  2. 2. What is the mistake people most often make with lfo?

  3. 3. In practice, which of these applies to lfo?

Ready for the full thing? Take the 25-question terminology test and get a certificate with your name and score.

SOURCES AND CITATIONS

Free, primary references for lfo — standards bodies, manufacturers, government offices and university course material. Each one lists the line of this entry it backs up.

  • Ableton — Learning Synths (opens in a new tab)

    Manufacturer learning resource · Ableton

    “Low-frequency oscillator: a slow wave used as modulation rather than sound.”— the claim this source supports

    Why it counts: A free, hands-on explainer from a DAW maker — useful for hearing the concept rather than only reading it.

  • Korg manuals (opens in a new tab)

    Primary reference · korg.com

    “Vibrato, tremolo and wobble bass all start here.”— the claim this source supports

    Why it counts: Published by the organisation responsible for the thing being defined, so it is a first-hand source rather than a summary of one.

RELATED TERMS IN SYNTHESIS AND SOUND DESIGN

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