In July 2003, Aaron Hunt suggested the general name 'Mu' for 'MIDI unit', and suggested that Greek prefixes be used to specify the number of bits resulting in the unit. Prefixes were offered and agreed upon by Aaron, Joe Monzo, Gene Ward Smith and John Chalmers.
The unit which called a 14mu (or "tetradekamu") is specified in the MIDI spec (1983) as the smallest increment available for the pitch-bend controller. Aaron Hunt prefers to call this unit simply "mu", whereas Monzo prefers to reserve "mu" for the general meaning of the term covering the whole family of different units.
Below is a table showing the number of bits resolution, the number of MIDI-units per semitone, the corresponding EDO, the approximate ratio of the MIDI-unit, and the cents-value of the interval. ("mu/ST" means "MIDI-units per semitone")
name bits mu/ST edo -------- ~ratio -------- ------ exact cents ------
----- 0 1 12 1.059463094 18:17 100
1mu / enamu 1 2 24 1.029302237 35:34 50
2mu / doamu 2 4 48 1.014545335 70:69 25
3mu / triamu 3 8 96 1.007246412 139:138 12 1/2 12.5
4mu / tetramu 4 16 192 1.003616666 555:553 6 1/4 6.25
5mu / pentamu 5 32 384 1.001806701 1109:1107 3 1/8 3.125
6mu / hexamu 6 64 768 1.000902943 2217:2215 1 9/16 1.5625
7mu / heptamu 7 128 1536 1.00045137 4433:4431 25/32 0.78125
8mu / oktamu 8 256 3072 1.000225659 8865:8863 25/64 0.390625
9mu / enneamu 9 512 6144 1.000112823 8864:8863 25/128 0.1953125
10mu / dekamu 10 1024 12288 1.00005641 17728:17727 25/256 0.09765625
11mu / endekamu 11 2048 24576 1.000028205 35456:35455 25/512 0.048828125
12mu / dodekamu 12 4096 49152 1.000014102 70913:70912 25/1024 0.0244140625
13mu / tridekamu 13 8192 98304 1.000007051 141825:141824 25/2048 0.01220703125
14mu / tetradekamu 14 16384 196608 1.000003526 283608:283607 25/4096 0.006103515625
See the individual entries for each MIDI-unit for more information.
The tonalsoft.com website is almost entirely the work of one person: me, Joe Monzo. Please reward me for my knowledge and effort by choosing your preferred level of financial support. Thank you.