The diatonic interval signatures of Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian — and what makes each mode sound like itself.
The word diatonic in music theory has a specific meaning: it refers to the seven-note scale system built from the natural pitches of a major scale. Every diatonic scale has the same internal structure — five whole steps and two half-steps in a specific arrangement. But the same seven notes can be reorganized to form seven different modes: Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Each mode has a distinctive sound, and that sound comes from the specific intervals between the tonic of the mode and the other six notes — what we call the interval signature of a mode. This guide is the complete tour of those interval signatures.
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Diatonic means built from the notes of a particular diatonic scale. A diatonic interval occurs naturally between two notes of a chosen diatonic scale — no notes outside the scale are required. This is different from a chromatic interval, which requires notes outside the scale. In C major, C-to-E is diatonic (both notes are in C major). C-to-E♭ is chromatic in a C major context because E♭ is not in C major.
Diatonic intervals form the natural harmonic vocabulary of any key. For the purposes of this guide, the focus is on diatonic intervals measured from each mode's tonic to each of the other six scale degrees — these six intervals form the interval signature of that mode.
Key insight
Even though all seven modes share the same seven pitches (when built on the same parent major scale), they have different interval signatures from their tonics. C Ionian's signature is measured from C; D Dorian's from D. The same pitches produce different intervals depending on which note is the tonic. This is why modes sound different despite sharing the same pitch collection.
All seven modes share the same seven pitches when they are modes of the same parent major scale. The modes of C major, for example: C Ionian starts on C (1st degree), D Dorian starts on D (2nd degree), E Phrygian on E (3rd), F Lydian on F (4th), G Mixolydian on G (5th), A Aeolian on A (6th), B Locrian on B (7th).
The general rule: Ionian on 1, Dorian on 2, Phrygian on 3, Lydian on 4, Mixolydian on 5, Aeolian on 6, Locrian on 7. To play G Mixolydian, find the major scale where G is the 5th degree — that's C major. G Mixolydian uses C major pitches but treats G as the tonic.
The Seven Mode Interval Signatures — from C
Each mode shown with C as tonic for direct comparison. Tonic = red. Characteristic interval = gold. Other notes = dim gold.
Explore All Seven Modes
Pick a tonic. Hear each mode. Compare interval signatures side by side with a drone reference.
Ionian is the standard major scale. Its interval signature from the tonic contains only perfect and major intervals: 1→2 is a major 2nd (2 semitones), 1→3 is a major 3rd (4 semitones), 1→4 is a perfect 4th (5 semitones), 1→5 is a perfect 5th (7 semitones), 1→6 is a major 6th (9 semitones), and 1→7 is a major 7th (11 semitones). There are no minor intervals anywhere from the tonic.
This is what gives Ionian its bright, settled, stable character. The absence of any minor intervals from the tonic means every harmonic relationship is either perfect or major — as consonant as diatonic intervals get.
Characteristic interval: the major 7th (leading tone)
One half-step below the octave, the major 7th creates a strong upward pull toward the tonic. Modes lacking the major 7th — like Aeolian with its minor 7th — feel more open or unresolved by comparison. The leading tone makes V→I cadences feel conclusively resolved, which is why Ionian is the home of most Western pop, classical, and folk music.
Dorian is the second-degree mode — built from D when the parent is C major. Its interval signature: 1→2 is a major 2nd, 1→3 is a minor 3rd, 1→4 is a perfect 4th, 1→5 is a perfect 5th, 1→6 is a major 6th, 1→7 is a minor 7th. The minor 3rd gives it a minor flavor, but the major 6th is what sets it apart.
In natural minor (Aeolian), the 6th is minor. In Dorian, the 6th is raised to major. This single interval change transforms the mode's character — less somber than Aeolian, more contemplative or folk-like.
Characteristic interval: the major 6th
Dorian appears throughout Celtic and folk music (the so-called "Celtic sound" often comes from Dorian's bright 6th), jazz improvisation (D Dorian over Dm7 chords), and modal jazz — Miles Davis's "So What" is built on D Dorian. In rock and pop, "Eleanor Rigby" and "Smoke on the Water" draw heavily on Dorian modal color. To make a passage sound clearly Dorian, feature the major 6th prominently.
Phrygian is the third-degree mode — built from E in C major. Its interval signature: 1→2 is a minor 2nd, 1→3 is a minor 3rd, 1→4 is a perfect 4th, 1→5 is a perfect 5th, 1→6 is a minor 6th, 1→7 is a minor 7th. This is the darkest of any diatonic mode — both the 2nd and 6th are minor.
The minor 2nd at the start is Phrygian's defining feature. A half-step right next to the tonic creates tension on every melodic move from the tonic to the 2nd degree. In E Phrygian, F♮ sits just a half-step above E — the smallest possible diatonic interval. Resolve melodic phrases on the tonic via a descending half-step from the 2nd.
Characteristic interval: the minor 2nd
Phrygian is fundamental to Spanish and Flamenco music (the Andalusian cadence), heavy metal's aggressive darkness, and Middle Eastern and Mediterranean music broadly. It appears in film scoring for tension and menace. Related: Phrygian dominant — Phrygian with a major 3rd instead of minor 3rd — is even more "Spanish" and central to Flamenco.
Lydian is the fourth-degree mode — built from F in C major. Its interval signature: 1→2 is a major 2nd, 1→3 is a major 3rd, 1→4 is an augmented 4th (the tritone — 6 semitones), 1→5 is a perfect 5th, 1→6 is a major 6th, 1→7 is a major 7th. Lydian has the augmented 4th — the tritone — between the tonic and the 4th scale degree. It is the only diatonic mode where the natural 4th is raised to a tritone.
Compared to Ionian, just this one interval changes, but it transforms the mode completely. Lydian sounds brighter than even Ionian — uplifting, transcendent, sometimes otherworldly. Without the augmented 4th audible, Lydian collapses back into Ionian.
Characteristic interval: the augmented 4th — no contest
Lydian is beloved in film scoring for wonder and magic — John Williams uses Lydian-flavored harmony throughout Star Wars, and Danny Elfman's Simpsons theme opens with a Lydian leap. It appears throughout jazz fusion (Pat Metheny, Allan Holdsworth) and progressive rock (Dream Theater, Tool). The "Lydian chord" is a major chord with ♯11: Cmaj7♯11 = C–E–G–B–F♯.
Mixolydian is the fifth-degree mode — built from G in C major. Its interval signature: 1→2 is a major 2nd, 1→3 is a major 3rd, 1→4 is a perfect 4th, 1→5 is a perfect 5th, 1→6 is a major 6th, 1→7 is a minor 7th. Mixolydian is Ionian with one change: the 7th is minor instead of major.
This single interval removes the leading-tone function and introduces a bluesy, modal-folk quality. Mixolydian sounds like major but without the strong cadential pull toward the tonic. The flat-VII chord — a major chord built on the ♭7th degree (F major in G Mixolydian) — is a classic Mixolydian move in countless rock songs.
Characteristic interval: the minor 7th (the ♭7)
Mixolydian appears throughout blues and rock ("Sweet Home Alabama," "Born on the Bayou," "Hard Day's Night"), Celtic traditional music, funk and soul (James Brown), and pop with a bluesy flair. The progression G–F–G is a quintessential Mixolydian move in rock — the ♭VII chord in major context is the unmistakable Mixolydian fingerprint.
Aeolian is the sixth-degree mode — built from A in C major — and is identical to the natural minor scale. Its interval signature: 1→2 is a major 2nd, 1→3 is a minor 3rd, 1→4 is a perfect 4th, 1→5 is a perfect 5th, 1→6 is a minor 6th, 1→7 is a minor 7th. Three minor intervals from the tonic — the 3rd, 6th, and 7th — give Aeolian its dark, somber, melancholic sound.
The minor 6th is what separates Aeolian from Dorian within minor-flavored modes. Compared to Phrygian, Aeolian has a major 2nd (not minor 2nd), making it less ominous. Aeolian is the default minor mode of Western music — "key of A minor" simply means A Aeolian. Most "sad" pop songs and classical minor-key works are in Aeolian.
Characteristic interval: harder to pin to one
Aeolian is the default minor — it sounds "minor" without any additional qualifiers. The best way to make a passage sound specifically Aeolian (rather than Dorian or Phrygian) is to avoid the bright major 6th of Dorian and the dark minor 2nd of Phrygian. Stick to the natural minor pattern and you are in Aeolian territory.
Locrian is the seventh-degree mode — built from B in C major. Its interval signature: 1→2 is a minor 2nd, 1→3 is a minor 3rd, 1→4 is a perfect 4th, 1→5 is a diminished 5th (the tritone — 6 semitones), 1→6 is a minor 6th, 1→7 is a minor 7th. The diminished 5th between the tonic and 5th degree makes Locrian uniquely unstable among diatonic modes.
The tonic chord of Locrian is itself diminished: B–D–F = B diminished triad. Diminished chords are inherently unstable — Locrian is trying to be its own tonic while simultaneously sounding like it wants to resolve somewhere else. This creates a perpetually unresolved feeling, which is why Locrian is rarely used as the home mode of a complete piece.
Characteristic interval: the diminished 5th
Locrian appears in jazz improvisation over half-diminished 7th chords (m7♭5), in film scoring for unsettling or surreal moments, and in some progressive metal and avant-garde contexts. Related: Locrian ♮2 — Locrian with a major 2nd instead of minor 2nd — is sometimes more practical in actual composition.
With all seven signatures laid out together, the patterns become visible — and you can build an ear-identification strategy from them.
★ = characteristic interval for that mode. Green = perfect, white = major, blue = minor, gold = augmented/diminished.
Key observations
Ear-identification decision tree
Step 1 — Hear the 3rd:
Step 2 — Narrow within major-3rd group:
Step 2 — Narrow within minor-3rd group:
Mode Identification Ear-Training
Hear a passage. Identify which mode it's in. Learn to hear modal signatures.
Improvise in Any Mode
Pick a mode. Get a backing track. Play melodies that emphasize the mode's characteristic intervals.
A diatonic interval is an interval that occurs naturally between two notes of a diatonic scale, without requiring any notes outside that scale. In C major, for example, C-to-G is a diatonic perfect 5th because both C and G belong to C major. C-to-G♭ would not be diatonic in C major because G♭ is outside the scale. Diatonic intervals are the building blocks of all tonal harmony within a given key.
The seven modes of C major share the same seven pitches, but each mode has a different tonic — the note the ear orients to as "home." When the ear establishes a tonic, it processes all other notes as intervals relative to that tonic. Change the tonic and you change all six interval relationships simultaneously. C treated as tonic produces Ionian's bright signature; A treated as tonic over the same pitches produces Aeolian's somber signature. The pitch collection is identical — the interval relationships are entirely different.
Exactly one note: the 6th degree. In Aeolian (natural minor), the 6th is a minor 6th from the tonic — dark and somber. In Dorian, the 6th is raised to a major 6th — brighter and more contemplative. All other intervals are identical between the two modes. This single note difference creates a noticeably different emotional quality. Dorian is more hopeful and folk-like; Aeolian is more melancholic and resigned. Aeolian goes to the darker, more "naturally minor" place.
The augmented 4th — the tritone — between the tonic and the 4th scale degree. In C Lydian, this is the interval C to F♯. This raised 4th gives Lydian its bright, uplifting, and sometimes otherworldly sound. Without it, Lydian is indistinguishable from Ionian. Feature the augmented 4th — melodically or harmonically — and the mode's character becomes unmistakable. This is why the Lydian chord (maj7♯11) is sometimes called the "Lydian chord": the ♯11 is just the augmented 4th above the root.
Because the tonic chord is diminished. In B Locrian, the chord built on the tonic (B–D–F) is a diminished triad — inherently unstable, built around the tritone between B and F. A diminished chord constantly signals the need to resolve elsewhere. When the home base itself sounds like it wants to move, establishing tonal center becomes very difficult. Composers and improvisers typically use Locrian over passing diminished or half-diminished harmonies rather than as the primary tonal center of a section.
Identify the characteristic interval of the mode you want to use: Dorian = major 6th, Phrygian = minor 2nd, Lydian = augmented 4th, Mixolydian = minor 7th. Then feature that interval prominently in your melody and harmony. In Dorian, linger on the major 6th and resolve to the tonic. In Lydian, leap up to the raised 4th. In Mixolydian, resolve phrases to the minor 7th before the tonic. In Phrygian, approach the tonic from the half-step above. The characteristic interval is what makes each mode audibly distinct — and it's what listeners unconsciously recognize as the mode's identity.
The seven diatonic modes share the same seven pitches. The same C major scale generates Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian — depending on which note you treat as the tonic. What changes is the interval relationships from that tonic.
Each mode has its own characteristic interval signature. Each signature produces a different harmonic and emotional landscape. Master the interval signatures, and you've mastered the modes.
The intervals tell you everything about how each mode wants to be used — which notes are the colors, which are the anchors, which create the characteristic sound. Modes aren't really separate from interval theory; they are interval theory, organized around different tonics.
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