FreeLesson 9 of 12 · Music theory · 19 min read

Basic intervals

The distance between two notes: the key to singing in tune by ear.

Practice what you're readingWrite the idea on the staff and hear it. No need to finish reading first.

What an interval is

It's the distance between two pitches. Recognizing them by ear lets you sing in tune without relying on an instrument.

Practice them

Link each interval to a familiar song and train them with the ear tool until you recognize them instantly.

How they're measured

Intervals are measured by how many notes they span (second, third, fourth...) and by their quality (major, minor, perfect). A major third and a minor third cover the same 'named' distance but sound different because they contain a different number of semitones.

Sing them, don't just listen

Recognizing an interval by ear sticks much faster if you also sing it: pick a reference note, sing the interval you're practicing above or below it, and check with the tuner whether you landed on the right note.

Common mistakes

The most common one is mixing up neighboring intervals, like a major third with a minor third, or overshooting an octave without noticing when singing upward. Practicing slowly and checking each note with your trained ear keeps the mistake from becoming a habit.

Melodic and harmonic

The same interval can appear two ways: melodic, when the notes sound one after the other (as inside your line), and harmonic, when they sound together (as between your voice and a second voice). Training both matters: the melodic one gives you in-tune leaps within the melody; the harmonic one lets you hear the distance against another voice without losing your own.

Perfect, major and minor

Each interval's family tells you how it behaves: unison, fourth, fifth and octave are 'perfect'; second, third, sixth and seventh come in major or minor versions, one semitone apart. C–E is a major third; E–G, a minor third: same name, different size and different color. Singing them from the tonic of a familiar key (C–E, E–G, C–G in C major) locks them in faster than memorizing them in isolation.

Ascending and descending: two different ears

Recognizing a fifth going up doesn't guarantee recognizing it going down: the ear processes them as different experiences, and almost everyone has descending intervals less trained. The rule: every interval is practiced in BOTH directions, with separate anchors for each (your song for the ascending major third won't help with the descending one — find another that starts by falling that distance). In the app, alternate rounds of ascending only, descending only, and mixed: mixed is the real exam.

The tritone and the difficult intervals

Between the perfect fourth and the perfect fifth lives the tritone (augmented fourth or diminished fifth): exactly three whole tones, the most unstable interval in the system — so tense that early music nicknamed it 'diabolus in musica'. Worth knowing for two reasons: it's the classic error when singing fifths (you landed a semitone short), and it's the tension that defines the dominant chord. Its uncomfortable neighbor is the minor second, the minimum distance, pure friction. Listen to them on purpose until their instability is unmistakable: well-recognized 'ugly' intervals tune the pretty ones.

Intervals inside a key: degrees and tendencies

An isolated interval is a distance; inside a key, it's a CHARACTER. The distance from the tonic defines each degree's color: a major third from the tonic says 'you're in major', and the seventh degree (the leading tone) sits a minor second below the tonic — which is why it 'wants' to rise so strongly. When you sing a melody you're not singing abstract intervals but degrees with tendencies. A revealing exercise: sing the scale and stop on the 7th degree — feel the discomfort — then resolve. That pull is what voice leading manages.

A ten-minute ear routine

The ear grows with small, frequent doses, not marathons. A format that works: three minutes of anchor songs (sing each opening and name its interval), four minutes of rounds in Ear training (note your percentage), and three minutes singing intervals from a tonic with the tuner as judge. Progression rule: when a set gives you 8 out of 10 or better three days in a row, add ONE new interval to the set. Within weeks, recognition turns from calculation into reflex.

Practice on the staff

Write each interval from C4: the third (E), the fifth (G) and the octave (C5), always returning to the low C. Listening back you'll recognize each leap.

GoalC4E4C4G4C4C5

Tap the staff to write at that pitch; tap a written note to erase it. With the keyboard: ↑/↓ pick the pitch, Enter writes, Backspace undoes.

Meter

Put it into practice

What you just read is trained on the platform: open Ear training and apply it now, with real feedback.

Open Ear training

Practice resources

Real material to take the lesson into the rehearsal room: the printable guide with the step-by-step routine, plus the exercises as MIDI files ready to play or import into your tools.

Printable practice guideTimed routine, exercises, weekly progression and a checklist. Print it or save it as a PDF.

Reference intervalsSix pairs from C4 (M2, M3, P4, P5, M6 and octave), each followed by a rest so you can sing it back.

MIDI files are generated the moment you download them and open in any player, DAW or score app. They are written from C4: transpose them to your voice range with the tools.