(music) A musical interval of the Western twelve-semitone system consisting of eleven semitones and spanning seven degrees of the diatonic scale. It is one semitone wider than a minor seventh and enharmonically equivalent to a diminished octave.
The major seventh has a pitch ratio close to 17:9.
Thus, suppose a fundamental 256 has present with it overtone harmonics 512, 768, 1024, 1280, &c., and that we sound with it the major seventh with fundamental 480, and having harmonics 960, 1440, &c. The two sets may be arranged thus c 256 512 768 1024 1280 h 480 960 1440, and we see that the fundamental of the second will beat 32 times per second with the first overtone of the first, giving dissonance.
The very marked dissonance of the major seventh is thus explained.
Thus, take the major seventh with frequencies 256 and 480.
The example we have given above of the major seventh must serve here.
They also employ four part minor and major seventh chords compared to the triads used exclusively in the previous section.