Major Seventh

Count letter names inclusively: C, D, E, F, G, A, B. That makes the interval a seventh.

C to B covers eleven semitones, so it is a major seventh. C to B flat covers ten and is a minor seventh.

C to C flat also covers eleven piano semitones in equal temperament, but the letter count reaches C. That spelling is a diminished octave.

Invert C-B by moving C above B. The result is B-C, a minor second.

Interval numbers under inversion add to nine: 7 plus 2. Major quality becomes minor.

Both intervals place their pitch classes one semitone apart, but the sounding notes occupy different registers. The inversion is useful for checking the interval and hearing its close relation to the octave.

An ascending C-B leap crosses most of an octave. A descending B-C reverses the direction and register.

Large leaps are easier to sing accurately when you first hear the destination against the tonic. Practice C-B-C so B is framed as the note immediately below the upper C.

In tonal melodies, B more often moves by step to C than it leaps from a lower C. The scale degree and the interval from the tonic describe two views of the same pitch.

In C major, B is scale degree 7 and lies one semitone below C. Tonal harmony often treats it as the leading tone.

B does not physically require a resolution. Repetition, meter, harmony and style determine whether the listener expects C next.

The pull becomes especially clear in G7-C: B rises to C while F commonly falls to E.

Cmaj7 contains C-E-G-B. The interval from its root C to B is a major seventh.

Inside the full chord, E and G confirm a C-major triad while B adds the major seventh. That harmonic frame differs from hearing only C and B as an exposed two-note sonority.

CmMaj7 also contains C-B, but combines it with the minor third E flat. The seventh keeps its interval name while the full chord quality changes.

Context changes which relationships your ear follows.

With only C and B, the semitone relation between B and the octave C is exposed. In Cmaj7, E and G establish a recognizable major chord, and B can be heard as an added chord tone within that larger sonority.

Register, spacing, timbre and volume also affect roughness. A widely voiced chord does not erase the interval; it changes how prominently its interaction is heard.

The octave is one semitone wider. The minor seventh is one semitone narrower.

On the staff, a diminished octave may use the same equal-tempered keys but has a different spelling and function.

In chord symbols, Cmaj7 means C major with a major seventh. C7 means C major with a minor seventh. The word maj describes the seventh in the first symbol.

Equal temperament sets the major seventh at 1,100 cents.

A 15:8 just major seventh is about 1,088 cents, roughly twelve cents narrower. Other tuning systems place it differently according to harmonic context.

The semitone count and written interval remain useful across systems, while the exact frequency ratio can vary.

Play C-B-C slowly and sing the upper C before you play B. This connects the major seventh to its one-semitone distance below the octave.

Compare C-B flat, C-B and C-C without changing the lower note.

Then play C and B alone, followed by C-E-G-B. Identify which notes were added and describe how the larger chord changes what you hear.