OTC 5L 5s

Omnitetrachordal MOS scale

5L+5s

10 tones (4+2+4)

temperament: blackwood

This scale has some unusual properties:

• it has only two modes
• either mode may be split in any of the three possible omnitetrachordal ways (9/8-4/3-4/3, 4/3-9/8-4/3, 4/3-4/3-9/8)
• it is its own dual (changing all L to s, and vice versa, gives the same scale)
• the (imperfect) tunings of 9/8 and 4/3 are independent of L/s ratio

See also OTC 7L+7s (whitewood) and OTC 12L+12s (catler/compton), which have similar properties.

P = undefined (or -1?)

Q = 5.6500418817 (4/3 = 2L+2.5s)

L = 120.00 to 240.00 cents (203.91 cents @ Q)

s = 0.00 to 120.00 cents (36.09 cents @ Q)

9/8 = L+s (240.00 cents for any L/s)

4/3 = 2L+2s (480.00 cents for any L/s)

generator = s (0.00 to 120.00 cents)

period = 1/5 octave (240.00 cents)

notable EDOs: 15, 20, 25

all modes:

Ls LsLs LsLs	LsLs Ls LsLs	LsLs LsLs Ls
sL sLsL sLsL	sLsL sL sLsL	sLsL sLsL sL

See also

• Omnitetrachordality
• Gallery of omnitetrachordal scales