Step label spectrum

Revision as of 17:44, 28 March 2024 by Frostburn (talk | contribs) (Change recommendation to favor M and uppercase letters in general. Use the S rule for negative steps too.)

Musical scales come in many varieties, but as long as they're ascending and periodic they can be broken down into a finite list of steps stacked on top on each other.

Now that abstract scale display is coming to Scale Workshop we need a system for indicating the sizes of steps that is both human readable and machine executable.

Positive-size step indicators

Below is a list of adjectives related to size ordered simulteneously in ascending ASCII order and descending size order.

  • Biggest
  • Colossal
  • Enormous
  • Gigantic
  • Huge
  • Large
  • Medium
  • Normal
  • minute
  • narrow
  • petite
  • small
  • tiny
  • unnoticeable
  • wee
  • zilch

The bolded first letter is intended as a shorthand for step patterns like L, M and s in LLsLLLs for Ionian or LMLsLsLMLs for Blackdye Grave Dorian.

The zilch step is reserved for steps of zero size i.e. repeated notes in the scale.

The anonymous x step is used if there are only steps of one size.

The unspecific S step is used if there is a single positive alongside the zero step.

Standard letters

For each naïve variety (count of step sizes, not to be confused with variety w.r.t. all interval classes) there is a standard set of letters to use. If possible the sets come in alphabetical order and with an equal number of uppercase and lowercase letters (or one more uppercase letter if the variety is odd).

Standard letters per variety
Naïve variety Letters Example Name
1 x xxxxx 5edo
1+0 S, z SSzSSzS 5edo with repeated steps
2 L, s LsLsLsL Sothic
3 L, M, s LMLsLLsLM Diasem Melodic Minor
4 L, M, n, s nMLsLMnMLM Zarlino[10]
5 H, L, M, n, s sHnHsHMLH Zil[9]
6 H, L, M, n, s, t
7 B, H, L, M, n, s, t
8 B, H, L, M, n, s, t, u
9 B, G, H, L, M, n, s, t, u
10 B, G, H, L, M, n, p, s, t, u

If there are more step sizes than available in the mnemonic list the whole Latin alphabet should be used, again dividing evenly w.r.t. upper- and lowercase.

Negative-size step indicators

Machine processing requires standard indicators for descending steps in cases where the user enters unsorted data in error or to enhance playability of the layout.

The Greek lowercase letters are used starting with µ due to its association with the metric predix micro followed by ε due to association with size in mathematics. Note that ε comes before µ in the Greek alphabet so it's intended for the descending step closer to zero. (Also note that this wiki article uses the Latin micro sign µ instead of the actual Greek μ as a reminder that in machine context the correct codepoint should be used to aid in automatic processing even if there is little difference in visual appearance.)

If there is one positive step size among negative steps S should be used to indicate it.

If there are more than two negative step sizes the whole Greek alphabet should be used.

Example

The "Ionian" mode with step sizes 2 and -1 in 8edo would be spelled SSµSSSµ.