Major Seventh · Theory

Seventh Chord Dominant Seventh Minor Seventh Half-Diminished Seventh

A major seventh is a major triad plus a major seventh:

C major seventh = C–E–G–B

It differs from the dominant seventh by a single semitone: B♭ becomes B. That half-step changes the tension completely.

Why it sounds sharp

The major seventh spans 11 semitones — one semitone short of the octave (see octave). So the seventh keeps being heard as an octave that has not arrived: the ear expects C and the note stops a semitone short. That almost-there suspension is the specific edge of a major seventh chord.

Position of the seventh	Interval	Impression
two semitones below the octave (minor seventh)	soft instability	dominant seventh
one semitone below the octave (major seventh)	sharp suspension	major seventh

Where it appears

Stacking thirds on a major scale produces natural major seventh chords on degrees 1 and 4 (Imaj7, IVmaj7). Minor keys do not produce it without chromatic alteration.

In traditional harmony it is rarely a destination. In the twentieth century it became a stable colour chord: in jazz and city pop a major seventh is often the end of a phrase, needing no resolution. A textbook case of harmonic function shifting with style.

Diagram: the seventh sitting a semitone below the octave

Listen: the major seventh

Hear the almost-arriving-and-stopping quality, then compare it with the dominant seventh.

Common misconceptions

"Major and dominant sevenths differ by one note, so they are alike." The seventh differs by a semitone and the tension is completely different — soft for the minor seventh, sharp for the major.
"A major seventh must resolve." Usually true traditionally; in jazz and pop it is a stable endpoint.
"Major sevenths only exist in major keys." They arise naturally on degrees 1 and 4 of a major scale; minor keys need accidentals.
"The word major makes it 'stronger' than a dominant seventh." "Major seventh" names the *size* of the seventh, not the chord's strength or function.

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Listen in the library

Suite bergamasque: III. Clair de luneC14:36Debussy's Clair de lune — major sevenths and ninths used as sustained colour rather than tension, the chord in another vocabularyDetailsScales, Arpeggios, and CadencesC13:22Scale exercises can sound a major-seventh arpeggio, making the seventh's closeness to the octave audibleDetailsSound Ye the Trumpet CallC10:35An organ hymn as a control — the major seventh is rare in traditional harmony, contrasting sharply with the aboveDetails

All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).

Sources

大七和弦 = 大三和弦 + 大七度；根音到七音为 11 个半音，属和声学通则
大七和弦在 20 世纪和声与爵士中成为稳定的色彩和弦，为通行表述

Used for fact-checking only; all prose is original.

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