Fifth complement

The fifth complement of a given interval is its interval distance from the fifth (3/2). It's very similar to the octave complement, but makes not much sense for intervals less than a fifth (since there is no "fifth reduction"). It seems to be very useful to describe the relation of thirds.

History

The term was seemingly coined by FloraC in September 2020.

Examples

The following interval pairs are fifth complementary to each other

• 5/4 and 6/5
• 19/16 and 24/19
• 9/8 and 4/3

See also

• Octave complement