MOS substitution
MOS substitution is a procedure for obtaining a ternary (3 step sizes) scale from two MOS patterns. It consists of taking one MOS pattern (called the template MOS), choosing a step size, and overwriting all instances of that step size using the step pattern of another MOS pattern (called the filling MOS). Unlike MV3 scales, a MOS substitution scale may have any combination of step sizes.
Examples
Many familiar ternary scales can be constructed as MOS substitutions.
LMsLMLs <- LLsLLLs x LMLML, LssLsLs x MsMs, sMssMss x LsLLs
LLmLLLs <- LLsLLLs x ms
LMsLM <- LLsLL x LMLM
The three standard diaslen scale patterns, denoted 4sL (LsLsLmLsLsm), 4sC (LmLsLsLmLss), and 4sR (LsLmLsLsLms), may be constructed via MOS substitution, giving generator sequences for the three scales:
| chirality | filling MOS | step pattern | generator sequence | ||
|---|---|---|---|---|---|
| template MOS: | LXLXLXLXLXX
|
intvl. class of gen.: | 2-steps | ||
| 4sC | mssmss
|
LmLsLsLmLss
|
GS(L+m, L+s, L+s) | ||
| 4sR | smssms
|
LsLmLsLsLms
|
GS(L+s, L+m, L+s) | ||
| 4sL | ssmssm
|
LsLsLmLsLsm
|
GS(L+s, L+s, L+m) | ||
