10et

10-ET, or ten-tone equal temperament, is a musical tuning in which the octave is divided into ten equal steps. Each step is 120 cents, so the octave spans 1200 cents and there are ten pitch classes per octave. The system is part of the broader family of equal temperaments and is considered a microtonal alternative to the standard 12-ET.

In 10-ET, the scale and harmonies are built from increments of a single step, which leads to distinctive intervallic relationships compared with 12-ET. Because all intervals are multiples of 120 cents, consonance with just intonation is only approximate. For example, a major third (near 386 cents in just intonation) is typically represented by three steps (360 cents) in 10-ET, with a deviation of about 26 cents. A perfect fifth (about 702 cents in just intonation) would correspond to seven steps (840 cents) in 10-ET, a larger deviation of roughly 138 cents. This results in unique chord textures and scalable options that differ from those available in 12-ET.

Usage and notation: 10-ET is mainly explored in theoretical and experimental contexts rather than as a standard tuning for large-scale tonal music. It can be implemented in synthesizers and digital tuning systems that support arbitrary tunings, enabling composers and theorists to study alternative scales and voice-leading patterns. The notation typically involves numeric pitch classes (0–9) or mapped letter-name schemes with consistent accidentals to indicate the 10-step lattice.

See also: other equal temperaments, microtonal music, 12-ET.