Class: Musa::Scales::BebopDominantScaleKind

Inherits:

ScaleKind

• Object
• ScaleKind
• Musa::Scales::BebopDominantScaleKind

Defined in:

lib/musa-dsl/music/scale_kinds/bebop/bebop_dominant_scale_kind.rb

Overview

Bebop dominant scale kind.

BebopDominantScaleKind defines the bebop dominant scale, an eight-note scale that adds a chromatic passing tone (major 7th) to the Mixolydian mode. This allows chord tones to fall on downbeats during eighth-note runs.

Pitch Structure

8 degrees plus extended:

Scale Degrees (uppercase for major quality):

• I (tonic): Root (0 semitones)
• II (supertonic): Major second (2 semitones)
• III (mediant): Major third (4 semitones)
• IV (subdominant): Perfect fourth (5 semitones)
• V (dominant): Perfect fifth (7 semitones)
• VI (submediant): Major sixth (9 semitones)
• VII (subtonic): Minor seventh (10 semitones)
• VII# (leading): Major seventh (11 semitones) ← PASSING TONE

Bebop Principle

The added chromatic note ensures that:

• Chord tones (1, 3, 5, b7) fall on strong beats
• Non-chord tones fall on weak beats
• Creates smooth voice leading at tempo

Musical Character

The bebop dominant scale:

• Essential for jazz improvisation over dominant 7th chords
• Creates characteristic bebop sound at fast tempos
• Used by Charlie Parker, Dizzy Gillespie, and bebop masters

Usage

g_bebop = Scales[:et12][440.0][:bebop_dominant][67]
g_bebop[0].pitch  # G (67) - root
g_bebop[6].pitch  # F (77) - minor 7th
g_bebop[7].pitch  # F# (78) - major 7th (chromatic passing)

See Also:

• Abstract base class
• Mixolydian (7-note parent)
• Bebop major scale

Constant Summary

@@pitches =

[{ functions: %i[I _1 tonic first],
pitch: 0 },
             { functions: %i[II _2 supertonic second],
pitch: 2 },
             { functions: %i[III _3 mediant third],
pitch: 4 },
             { functions: %i[IV _4 subdominant fourth],
pitch: 5 },
             { functions: %i[V _5 dominant fifth],
pitch: 7 },
             { functions: %i[VI _6 submediant sixth],
pitch: 9 },
             { functions: %i[VII _7 subtonic seventh],
pitch: 10 },
             { functions: %i[VII# _8 leading eighth],
pitch: 11 },
             { functions: %i[VIII _9 ninth],
pitch: 12 },
             { functions: %i[IX _10 tenth],
pitch: 12 + 2 },
             { functions: %i[X _11 eleventh],
pitch: 12 + 4 },
             { functions: %i[XI _12 twelfth],
pitch: 12 + 5 },
             { functions: %i[XII _13 thirteenth],
pitch: 12 + 7 },
             { functions: %i[XIII _14 fourteenth],
pitch: 12 + 9 },
             { functions: %i[XIV _15 fifteenth],
pitch: 12 + 10 },
             { functions: %i[XV _16 sixteenth],
pitch: 12 + 11 }].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/bebop/bebop_dominant_scale_kind.rb', line 98

def grades
  8
end

.id ⇒ Object

# File 'lib/musa-dsl/music/scale_kinds/bebop/bebop_dominant_scale_kind.rb', line 102

def id
  :bebop_dominant
end

.pitches ⇒ Object

# File 'lib/musa-dsl/music/scale_kinds/bebop/bebop_dominant_scale_kind.rb', line 94

def pitches
  @@pitches
end