Genus (music) the other hand, also has twelve pitches to the octave, but the semitones are all of the same size. In contrast, the ancient Greek chromatic scale had seven tones to the octave (assuming alternating conjunct and disjunct tetrachords), and had incomposite minor thirds as well as semitones and whole tones. The (Dorian) scale generated from the chromatic genus is composed of two chromatic tetrachords: whereas in modern music theory, a chromatic scale is: The number and nature of the shades of the chromatic genus vary amongst the Greek theorists. The major division is between the Aristoxenians and the Pythagoreans. Aristoxenus
Octave (electronics) Octave (electronics) In electronics, an octave (symbol oct) is a logarithmic unit for ratios between frequencies, with one octave corresponding to a doubling of frequency. For example, the frequency one octave from (or above) 40 Hz is 80 Hz. The term is derived from the Western musical scale where an octave is a doubling in frequency. Specification in terms of octaves is therefore common in audio electronics. Along with the decade, it is a unit used to describe frequency bands or frequency ratios. A frequency ratio expressed in octaves is the base-2 logarithm (binary logarithm) of the ratio: An amplifier