Class: Musa::Scales::AlteredScaleKind

Inherits:

ScaleKind

• Object
• ScaleKind
• Musa::Scales::AlteredScaleKind

Defined in:

lib/musa-dsl/music/scale_kinds/melodic_minor/altered_scale_kind.rb

Overview

Altered scale kind (seventh mode of melodic minor).

AlteredScaleKind defines the Altered scale (also called Super Locrian, Diminished Whole Tone, or Altered Dominant), the seventh mode of the melodic minor scale. It's the quintessential scale for altered dominant chords in jazz.

Pitch Structure

7 diatonic degrees plus extended harmony:

Scale Degrees (lowercase for diminished quality):

• i (tonic): Root (0 semitones)
• ii (supertonic): Minor second (1 semitone) ← b9
• iii (mediant): Minor third (3 semitones) ← #9 (enharmonic)
• iv (subdominant): Major third (4 semitones) ← b11 (3rd of chord)
• v (dominant): Diminished fifth (6 semitones) ← b5/#11
• vi (submediant): Minor sixth (8 semitones) ← #5/b13
• vii (subtonic): Minor seventh (10 semitones) ← b7

All Alterations Present

Contains all possible alterations of a dominant chord:

• b9, #9 (altered 9ths)
• #11/b5 (altered 11th/5th)
• b13/#5 (altered 13th/5th)

Musical Character

The Altered scale:

• Maximum tension for dominant chords
• Used over 7alt, 7#9, 7b9#11, etc.
• Essential in bebop and modern jazz
• Creates strong resolution to tonic

Usage

g_alt = Scales[:et12][440.0][:altered][67]
g_alt.tonic  # G (67)
g_alt.ii     # Ab (68) - b9
g_alt.iii    # Bb (70) - #9
g_alt.v      # Db (73) - b5

See Also:

• Abstract base class
• Parent melodic minor scale
• Another altered dominant scale option

Constant Summary

@@pitches =

[{ functions: %i[i _1 tonic first],
pitch: 0 },
             { functions: %i[ii _2 supertonic second],
pitch: 1 },
             { functions: %i[iii _3 mediant third],
pitch: 3 },
             { functions: %i[iv _4 subdominant fourth],
pitch: 4 },
             { functions: %i[v _5 dominant fifth],
pitch: 6 },
             { functions: %i[vi _6 submediant sixth],
pitch: 8 },
             { functions: %i[vii _7 subtonic seventh],
pitch: 10 },
             { functions: %i[viii _8 eighth],
pitch: 12 },
             { functions: %i[ix _9 ninth],
pitch: 12 + 1 },
             { functions: %i[x _10 tenth],
pitch: 12 + 3 },
             { functions: %i[xi _11 eleventh],
pitch: 12 + 4 },
             { functions: %i[xii _12 twelfth],
pitch: 12 + 6 },
             { functions: %i[xiii _13 thirteenth],
pitch: 12 + 8 }].freeze

Class Method Summary

• .grades ⇒ Object
• .id ⇒ Object
• .pitches ⇒ Object

Constructor Details

This class inherits a constructor from Musa::Scales::ScaleKind

Class Method Details

.grades ⇒ Object

# File 'lib/musa-dsl/music/scale_kinds/melodic_minor/altered_scale_kind.rb', line 94

def grades
  7
end

.id ⇒ Object

# File 'lib/musa-dsl/music/scale_kinds/melodic_minor/altered_scale_kind.rb', line 98

def id
  :altered
end

.pitches ⇒ Object

# File 'lib/musa-dsl/music/scale_kinds/melodic_minor/altered_scale_kind.rb', line 90

def pitches
  @@pitches
end