Multiple Scales Simulation!ztclgJ4A!iT4W8iCBhbyOgpWSXgUBBgYOZuvUi0oRBsY6hkYd1Po
(Update: added popular mode for Roman numerals, fixed a bug with switching to another song scale)

In response to several discussions relating non-diatonic chords, I made a simplified simulation of what would happen in Hookpad if multiple scales are supported at the same time. It works on Windows machines only, but I could provide the source code if anyone wants to expand upon this demonstration, including the @Hooktheory staff.

Some notes:

  • Chords with an altered root do not have striped colour bars as in Hookpad;
  • Roman numerals in the popular style apply also to the extensions;
  • Chords with a minor third still display the alteration in the seventh anyway, so in C Major, i7 means CmM7, unlike Hookpad where it represents Cm7 (which would be i♭7);
  • Both the harmonic and melodic minor scales are in mode I mode VI, but using the source these scales could be reconfigured to be in mode I instead;
  • Currently there is no way to display a dimM7 chord in Roman numerals (it does not matter because no two adjacent scale degrees in any scale may form an augmented third).


  • Inversions with correct accidentals;
  • Behaviour of other extended chords, with proper Roman numeral spelling;
  • Applied chords (would this lead to applied chords on chromatic scale degrees by switching between scales?)

@Hertzdevil, I downloaded and used the simulation, this worked pretty much how I envisioned, many thanks for the prototype.