Class: Musa::Scales::MajorScaleKind Private

Inherits:
ScaleKind show all
Defined in:
lib/musa-dsl/music/scale_kinds/major_scale_kind.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Major scale kind (Ionian mode).

MajorScaleKind defines the major scale, the fundamental scale of Western tonal music. It follows the pattern: W-W-H-W-W-W-H (whole-half steps) or intervals: M2-M2-m2-M2-M2-M2-m2 from the root.

Pitch Structure

7 diatonic degrees plus extended harmony (8th-13th):

Scale Degrees (Roman numerals, uppercase for major):

  • 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, relative minor)
  • VII (leading): Major seventh (11 semitones)

Extended degrees (for extended harmony):

  • VIII-XIII: Compound intervals (8th, 9th, 10th, 11th, 12th, 13th)

Function Aliases

Each degree has multiple function names:

  • Numeric: _1, _2, _3, _4, _5, _6, _7 (ordinal)
  • Roman: I, II, III, IV, V, VI, VII (harmonic analysis)
  • Function: tonic, supertonic, mediant, subdominant, dominant, submediant, leading
  • Ordinal: first, second, third, fourth, fifth, sixth, seventh
  • Special: relative/relative_minor for VI (relative minor root)

Examples:

Scale degrees

c_major = Scales[:et12][440.0][:major][60]

c_major.tonic.pitch     # => 60  (C)
c_major.dominant.pitch  # => 67  (G)
c_major.VI.pitch        # => 69  (A, the relative minor's root)

Reaching the relative minor

c_major.relative_minor.pitch               # => 69
c_major.relative_minor.as_root_of(:minor)  # => a Scale

See Also:

Constant Summary collapse

@@pitches =

This classvariable is part of a private API. You should avoid using this classvariable if possible, as it may be removed or be changed in the future. 

[{ 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 relative relative_minor sixth],
pitch: 9 },
             { functions: %i[VII _7 leading seventh],
pitch: 11 },
             { functions: %i[VIII _8 eighth],
pitch: 12 },
             { functions: %i[IX _9 ninth],
pitch: 12 + 2 },
             { functions: %i[X _10 tenth],
pitch: 12 + 4 },
             { functions: %i[XI _11 eleventh],
pitch: 12 + 5 },
             { functions: %i[XII _12 twelfth],
pitch: 12 + 7 },
             { functions: %i[XIII _13 thirteenth],
pitch: 12 + 9 }].freeze

Class Method Summary collapse

Constructor Details

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

Class Method Details

.grades ⇒ Integer

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Number of diatonic degrees.

Returns:

  • (Integer) —

    7



99
100
101
 
# File 'lib/musa-dsl/music/scale_kinds/major_scale_kind.rb', line 99

def grades
  7
end

.id ⇒ Symbol

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Scale kind identifier.

Returns:

  • (Symbol) —

    :major



105
106
107
 
# File 'lib/musa-dsl/music/scale_kinds/major_scale_kind.rb', line 105

def id
  :major
end

.pitches ⇒ Array<Hash>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Pitch structure.

Returns:

  • (Array<Hash>) —

    pitch definitions with functions and offsets



93
94
95
 
# File 'lib/musa-dsl/music/scale_kinds/major_scale_kind.rb', line 93

def pitches
  @@pitches
end