SAMPLED

Music theory basics · updated 2026-08-16

JUST INTONATION

Tuning built from small whole-number frequency ratios. Intervals beat less, but the tuning only works cleanly in a limited set of keys.

Photograph of a printed score of Mozart's Rondo alla Turca open on a music desk, showing staves, key signature and note heads — the written notation this section defines.
Music theory basics — Photograph of a printed score of Mozart's Rondo alla Turca open on a music desk, showing staves, key signature and note heads — the written notation this section defines.

Photo: Music Sheet, Mozart's Alla Turca (opens in a new tab) by Schiller12 (opens in a new tab), via Wikimedia Commons — CC BY-SA 4.0 (opens in a new tab)

Key takeaways

  • Tuning built from small whole-number frequency ratios.
  • Intervals beat less, but the tuning only works cleanly in a limited set of keys.
  • The cost is that intervals differ from key to key, so a keyboard tuned justly in C sounds progressively worse the further you modulate.
  • Barbershop and a cappella groups drift into just intonation naturally because singers tune by ear to the chord rather than to a fixed grid.
  • Watch out: applying a just tuning table to a track that modulates.

Quick checklist

  • Can you define just intonation in one sentence without looking?
  • Can you point at just intonation 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?

JUST INTONATION IN DEPTH

Just intonation tunes intervals to whole-number frequency ratios — 3:2 for a fifth, 5:4 for a major third — so chords lock without beating. The cost is that intervals differ from key to key, so a keyboard tuned justly in C sounds progressively worse the further you modulate.

How it works in practice

Barbershop and a cappella groups drift into just intonation naturally because singers tune by ear to the chord rather than to a fixed grid.

The mistake people make

Applying a just tuning table to a track that modulates. The chords in the home key improve, and everything else gets audibly worse.

WHERE JUST INTONATION SITS

Just intonation belongs to music theory basics in the Sampled music glossary. The vocabulary you need before anyone can explain a chart, a chord chart, or a session to you.

TEST YOURSELF

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

  1. 1. Which statement best describes just intonation?

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

  3. 3. In practice, which of these applies to just intonation?

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 just intonation — standards bodies, manufacturers, government offices and university course material. Each one lists the line of this entry it backs up.

  • Stanford CCRMA — tuning systems (opens in a new tab)

    University research centre · Stanford CCRMA

    “Tuning built from small whole-number frequency ratios.”— the claim this source supports

    Why it counts: The CCRMA course material derives this from first principles, so you can check the maths behind the plain-English version above.

  • UC Berkeley CNMAT research (opens in a new tab)

    University research centre · UC Berkeley (CNMAT)

    “Intervals beat less, but the tuning only works cleanly in a limited set of keys.”— the claim this source supports

    Why it counts: Berkeley's research notes cover the implementation detail that day-to-day usage of the term skips over.

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