scale.rb

A scale is an ordered collection of tones.

Creating a Scale

Scale objects should be created by indexing the Scale class directly:

  Scale['Major']

An alternative method of resolving a chord is to use the resolve method, though this is likely to become deprecated in the future when chord progression support/representation is added:

  Scale.resolve(name)

Associations

• modes - Associated modes.
• main_mode - Associated mode with a mode index of 1 (first mode). This sometimes

    the only defined mode such as for the whole tone scale.
  

• tones - A collection of +ScaleTone+s.
• notes - An array of notes (delegated through tones)
• chords - A collection of associated chords with the first mode of this scale.

Modes

Each scale can have one or many modes, which really define the relationship to chords. Modes are accessible like so (all methods are equal):

  Scale['Major']['Dorian']
  Scale['Major'][2]
  Scale['Major'].modes['Dorian']
  Scale['Major'].modes[2]

Examples

Listing Tones in Scales

  Scale['Major'].notes
  # => ["C", "D", "E", "F", "G", "A", "B"]

  Scale['Major'].in_key_of('Eb').notes
  Scale['Eb Major'].notes  # Same as above
  # => ["Eb", "F", "G", "Ab", "Bb", "C", "D"]

Correctly Interpets Theoretical Keys (not just pitches)

  Scale['Gb Major'].notes
  # => ["Gb", "Ab", "Bb", "Cb", "Db", "Eb", "F"]
  # Note the use of Cb which is theoretically correct over enharmonic B.

Also correctly interpet tones off of enharmonic base keys:

  Scale['Gb Major'].notes
  # => ["Gb", "Ab", "Bb", "Cb", "Db", "Eb", "F"]
  Scale['F# Major'].notes
  # => ["F#", "G#", "A#", "B", "C#", "D#", "E#"]

Listing Tones within the context of a mode

  Scale['Major'].modes['Dorian']
  Scale['Major']['Dorian']  # Same as above
  # => ["D", "E", "F", "G", "A", "B", "C"]

  Scale['Melodic Minor'].modes['Super Locrian'].notes
  # => ["B", "C", "D", "Eb", "F", "G", "A"]  # aka. Altered Scale or Dim. Whole Tone

Listing Related Chords

  Scale['Major'].chords.symbols
  # => ['maj7', 'maj6', '6/9']
  Scale['Major']['Dorian'].chords.symbols
  # => ['min7', 'min6']