Musical Intervals - Frequency Ratios & Ear Training
Hear and compare all 12 chromatic intervals from unison to octave using the Dual Oscillator
Pre-configured to a Perfect Fifth — one of the most consonant intervals in music
What are Musical Intervals?
A musical interval is the distance in pitch between two notes. Intervals are the building blocks of melody (notes played sequentially) and harmony (notes played simultaneously). Each interval has a characteristic sound quality — from the perfect consonance of a unison or octave, to the tension of a tritone. Intervals can be described by the number of semitones between notes, or by their frequency ratio in just intonation (the system of tuning based on simple whole-number ratios).
All 12 Chromatic Intervals
Starting from C4 (middle C, 261.63 Hz). Just intonation ratios are shown — in equal temperament, intervals are slightly adjusted so that all keys sound equally good.
| Interval | Semitones | Just Ratio | Example | Listen |
|---|---|---|---|---|
| Unison | 0 | 1:1 | C4 + C4 | ▶ |
| Minor 2nd | 1 | 16:15 | C4 + C#4 | ▶ |
| Major 2nd | 2 | 9:8 | C4 + D4 | ▶ |
| Minor 3rd | 3 | 6:5 | C4 + Eb4 | ▶ |
| Major 3rd | 4 | 5:4 | C4 + E4 | ▶ |
| Perfect 4th | 5 | 4:3 | C4 + F4 | ▶ |
| Tritone | 6 | 45:32 | C4 + F#4 | ▶ |
| Perfect 5th | 7 | 3:2 | C4 + G4 | ▶ |
| Minor 6th | 8 | 8:5 | C4 + Ab4 | ▶ |
| Major 6th | 9 | 5:3 | C4 + A4 | ▶ |
| Minor 7th | 10 | 9:5 | C4 + Bb4 | ▶ |
| Major 7th | 11 | 15:8 | C4 + B4 | ▶ |
| Octave | 12 | 2:1 | C4 + C5 | ▶ |
The frequencies above use equal temperament (the standard tuning for modern keyboards and fretted instruments). The just intonation ratios show the idealized whole-number relationships — equal temperament slightly adjusts these to allow playing in any key.
Just Intonation vs Equal Temperament
In just intonation, intervals use exact whole-number frequency ratios (like 3:2 for a perfect fifth). These produce the purest, most beatless harmonies. However, just intonation only works perfectly in one key — when you transpose to another key, some intervals become noticeably out of tune. Equal temperament solves this by dividing the octave into 12 exactly equal semitones (each a ratio of the 12th root of 2, or approximately 1.05946). This means no interval is perfectly pure, but every key sounds equally good — a trade-off that has defined Western music since the 18th century.
Why Learn Intervals?
- Ear training — recognizing intervals by ear is fundamental to musicianship and sight-singing
- Composition and arranging — understanding how intervals create consonance, dissonance, and movement
- Tuning and acoustics — the physics of why certain intervals sound 'resolved' and others create tension