Just Intonation (Major)

Perfectly pure major thirds (5:4) and fifths (3:2) in the home key.

Quick Facts

Creator
Gioseffo Zarlino and Renaissance theorists
Historical Era
Renaissance / Theory
Formula Type
just-ratios
Key Advantage
Perfectly pure major thirds (5:4) and fifths (3:2) in the home key.
Key Limitation
Fixed tonal center — modulating to other keys produces out-of-tune intervals.
Typical Use
A cappella choral music, theoretical analysis, and tuning reference for pure intervals.

Mathematical Basis

Just intonation uses simple whole-number frequency ratios (5:4 major third, 3:2 fifth, 6:5 minor third) to achieve maximum harmonic purity in the home key. Intervals are pure but fixed to one tonal center.

Sound Character

Just intonation produces exceptionally pure consonances in the home key: major thirds (5:4), perfect fifths (3:2), and minor thirds (6:5) are all beatless. The result is a choir-like blend where chords fuse into a unified sound. Modulation causes increasing dissonance as the key moves away from the tonal center.

Just Intonation (Major) Frequency Table — All 12 Notes at A4=440Hz

Note Equal Temp. (Hz) Just Intonation (Major) (Hz) Cents from Equal
C4 261.626 261.626 0.00
Db4 277.183 275.311 -11.73
D4 293.665 294.329 +3.91
Eb4 311.127 313.950 +15.64
E4 329.628 327.032 -13.69
F4 349.228 349.624 +1.96
Gb4 369.994 367.910 -9.78
G4 391.995 392.439 +1.96
Ab4 415.305 411.570 -15.64
A4 440.000 436.043 -15.64
Bb4 466.164 470.927 +17.60
B4 493.883 490.548 -11.73

Frequencies in Hz at A4=440Hz. Positive cents = sharper than equal temperament. Negative = flatter. Formula: f = f_equal × 2(cents/1200)

Historical Context

Just Intonation (Major) originates from the Renaissance / Theory era, developed by Gioseffo Zarlino and Renaissance theorists. It was primarily used for A cappella choral music, theoretical analysis, and tuning reference for pure intervals..

Just intonation was championed by Renaissance theorist Gioseffo Zarlino as the ideal for vocal polyphony. It remains the natural tuning of unaccompanied choirs and a cappella ensembles.

Who Uses Just Intonation (Major) Today

Just intonation is used by a cappella choirs, barbershop quartets, and string quartets exploring pure intonation. It is the theoretical basis for understanding consonance and the physics of harmonic resonance.

Tune with Just Intonation (Major) — Get Tunable.

Tunable supports Just Intonation (Major) and 15 other tuning systems including equal temperament, Pythagorean, just intonation, and well temperaments. See exact Hz values in real-time as you play.

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