Harmonic seventh

[8] This is somewhat narrower than and is, "particularly sweet",[9] "sweeter in quality" than an "ordinary"[10] just minor seventh, which has an intonation ratio of 9:5[11] (about 1018 cents).

As a pitch relation (968.826 cents up from the reference or tonic note) rather than a scale-position note, a harmonic seventh is produced by different notes in different tuning systems: When played on the natural horn, the note is often adjusted to 16:9 of the root as a compromise (for C maj7♭, the substituted note is B♭-, 996.09 cents), but some pieces call for the pure harmonic seventh, including Britten's Serenade for Tenor, Horn and Strings.

[15][16][c][17] In quarter-comma meantone tuning, standard in the Baroque and earlier, the augmented sixth is 965.78 cents – only 3 cents below 7:4, well within normal tuning error and vibrato.

Pipe organs were the last fixed-tuning instrument to adopt equal temperament.

The harmonic seventh differs from the just 5-limit augmented sixth of ⁠ 225 / 128 ⁠ by a septimal kleisma (⁠ 225 / 224 ⁠, 7.71 cents), or about ⁠ 1 / 3 ⁠ Pythagorean comma.