David Brown's Lumatone Mapping Generator

This project contains a generator for Lumatone mappings. It is a fairly straightforward Rust project. cargo run will generate the various mapping files for each layout within the layouts/mappingname directories. It is not necessary to run the program, unless you make changes, as the mappings have been committed to the repository as well.

Currently, there are three things that go into a mapping:

• The Tuning. This describes enough to the program how a given tuning maps to MIDI notes, describes the intervals in that tuning, and gives names for the notes. Currently, there are three tunings available: EDO12, EDO19, and EDO31.
• The Layout. This describes the algorithm for building the mapping. There are two layouts implemented so far:
  • Wicki-Hayden. A layout that emphasizes the diatonic scale.
  • Harmonic Table. A layout that emphasizes harmonic relations. Scales are more difficult to play, but chords tend to be clustered closely.
• The FillInfo. This describes how the mapping will be placed on the keyboard. This describes what range is covered, as well as where the starting note (usually Middle C) is placed. Currently, a split layout, and a full keyboard (wide) are supported.

The combinations of these mappings are under the layouts directory. For each mapping, there is an .ltn file to load into the Lumatone editor, and an .svg file showing the mapping.

Mapping notes

For the Wicki-Hayden layout, all of the generated mappings are mostly useful. For EDO31, there isn't enough room in the split, so some of the double sharps are not present on the keyboard. They are all present on the right side, but the grouping is split (it is on the edges) so not really useful for playing. The wide version of EDO31, covers everything, but only a little over 4 octaves.

The harmonic table layout works well for EDO12 and EDO19. The split version isn't particularly useful, as it kind of limits what keys are available, and this layout covers sufficient range on its own.

EDO31 does not work with the harmonic table layout, as the layout is not generative within a single octave. The files are present, but a given note will only be available in every other octave.

Generation

This program is intended to make isomorphic mappings; mappings that are regular and defined by specific rules.

To make an isomorphic layout, there needs to be a generator. This describes the intervals that are along each axis of the mapping. Of the three axes, describing two of the intervals will define the third. The code currently doesn't check that the generator is consistent, and inconsistent intervals will result in a layout that depends on the fill algorithm used.

The FillInfo describes a starting key and gives left and right bounds. The algorithm will fill fully vertically.

The Layouts

Wicki-Hayden

The Wicki-Hayden layout is a layout I haven't seen used as much on the Lumatone. It places an emphasis on the diatonic scale. I found this to be one of the easiest layouts to learn to play (coming from the standard piano layout).

It looks like this with 12-EDO, split:

along with the layout files

For 19-EDO split:

along with the layout files

For 31-EDO, split:

along with the layout files

Due to size constraints, there are a few double sharps that are missing on the left half (the bass notes). There is a wide 31-EDO layout that doesn't have the missing keys, but covers a lot less range.

along with the layout files