Seventh

• Big Septima - an interval of seven steps or five and a half tones , indicated by b. 7

• Lesser septima - an interval of seven steps or five tones, indicated by m. 7

• Increased septima - an interval of seven steps or six tones. Designated by uv. 7 , anharmonically equal to a pure octave , practically not used in music.

• Decreased septima - an interval of seven steps or four and a half tones, denoted by the mind. 7 . Anharmonically equal to a large sixth .

Reduced septima at the VII stage of harmonic major and minor is a characteristic interval and is allowed in a pure fifth at the first stage (tonic). Can also be built:

• in major on the II increased and on the III (with the participation of II lower) steps. In both cases, the movement of one of the voices by half a ton is allowed in the minor sixth at the third stage.
• in minor on the IV increased and on the V (with the participation of the IV lowered) steps. In both cases, the movement of one of the voices by half a ton is allowed in the minor sextus at the fifth step.

In natural order, the frequency ratio of the extreme sounds of a large septim is 8:15 (b. 3 + h. 5), for a small septima it is either 5: 9 (m. 3 + h. 5) or 9:16 (h. 4 + part 4).

• Lesser Septima:

• Big Septima:

• Septaccord

• Solovyov N.F. Septima // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.