Topic summary
Utonal
Extracted from the Wikipedia article Otonality and utonality.
Definition
An otonality is a collection of pitches which can be expressed in ratios, expressing their relationship to the fixed tone, that have equal denominators and consecutive numerators. For example, 1/1, 5/4, and 3/2 (justmajor chord) form an otonality because they can be written as 4/4, 5/4, 6/4. This in turn can be written as an extended ratio 4:5:6. Every otonality is therefore composed of members of a harmonic series. Similarly, the ratios of a utonality share the same numerator and have consecutive denominators. 7/4, 7/5, 7/6, and 1/1 (7/7) form a utonality, sometimes written as 1/4:5:6:7, or as 7/7:6:5:4. Every utonality is therefore composed of members of a subharmonic series. This term is used extensively by Harry Partch in Genesis of a Music.