Class: Musa::Scales::BebopMinorScaleKind

Inherits:

ScaleKind

• Object
• ScaleKind
• Musa::Scales::BebopMinorScaleKind

Defined in:

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

Overview

Bebop minor scale kind.

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

Pitch Structure

8 degrees plus extended:

Scale Degrees (lowercase for minor quality):

• i (tonic): Root (0 semitones)
• ii (supertonic): Major second (2 semitones)
• iii (mediant): Minor third (3 semitones)
• iv (subdominant): Perfect fourth (5 semitones)
• v (dominant): Perfect fifth (7 semitones)
• vi (submediant): Major sixth (9 semitones) ← DORIAN
• vii (subtonic): Minor seventh (10 semitones)
• vii# (leading): Major seventh (11 semitones) ← PASSING TONE

Bebop Principle

The added major 7th chromatic note ensures that:

• Chord tones (1, b3, 5, b7) fall on strong beats
• Non-chord tones fall on weak beats
• Smooth chromatic connection from b7 to root

Musical Character

The bebop minor scale:

• Used over minor 7th chords
• Based on Dorian mode (bright minor)
• Common in jazz ii-V-I progressions

Usage

d_bebop_min = Scales[:et12][440.0][:bebop_minor][62]
d_bebop_min[6].pitch  # C (72) - minor 7th
d_bebop_min[7].pitch  # C# (73) - major 7th (passing)
d_bebop_min[8].pitch  # D (74) - octave

See Also:

• Abstract base class
• Dorian mode (7-note parent)
• Bebop dominant 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: 3 },
             { 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 + 3 },
             { 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_minor_scale_kind.rb', line 98

def grades
  8
end

.id ⇒ Object

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

def id
  :bebop_minor
end

.pitches ⇒ Object

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

def pitches
  @@pitches
end