218e Rewired

How to measure your 208. Read this first!

1. Set the volts per octave. Match the setting above to how your 208 is trimmed, and leave it there. A table measured at one scaling is wrong at the other. Measure against equal temperament.

2. Warm up for at least 30 minutes. The oscillator drifts as it comes up to temperature, often by more than the error you are correcting.

3. Tune the lowest C. Octave switch at its lowest setting, hold the lowest C, and trim the 208 until a tuner reads it exactly in tune. Everything else is measured against this note.

4. Play every note, note how far off it is. Work up from that C, changing octave as you run out of keys. Enter the tuner reading in cents. For example, +12 for 12 cents sharp, −7 for 7 cents flat.

5. Build, flash, check.

Use the Scale Workshop to build scales in the browser and export .scl files.

A file on its own needs twelve degrees, one per key. Add a .kbm keyboard mapping to a slot and it can have any number, repeating at whatever interval it declares — the octave controls step that interval. Empty slots keep the factory temperament.

A scale that repeats at the octave is shifted to make A sit at the same pitch in every slot, so switching tuning doesn’t need retuning. Which degree lands on the bottom C is up to the file: a scale published rooted on A needs rotating first. (Modify scale → Rotate mode in Scale Workshop) A scale that repeats at anything else is left where it is, with its first degree on the bottom key.

To switch between tunings, go into Edit mode and toggle key 27 or 28. The current tuning will be indicated by the rem en and trn LEDs.