Class: Musa::Scales::LydianScaleKind

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

Overview

Lydian mode (fourth mode of major scale).

LydianScaleKind defines the Lydian mode, a major mode with a characteristic raised fourth degree. It's built on the fourth degree of the major scale and has a bright, dreamy, floating quality.

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): Augmented fourth (6 semitones) ← CHARACTERISTIC
  • V (dominant): Perfect fifth (7 semitones)
  • VI (submediant): Major sixth (9 semitones)
  • VII (leading): Major seventh (11 semitones)

Key Difference from Major

The IV degree is raised from 5 semitones (perfect fourth) to 6 semitones (augmented fourth/tritone), creating:

  • A bright, ethereal quality
  • The characteristic "Lydian color"
  • A sense of floating or suspension

Musical Character

The Lydian mode:

  • Maintains major quality (major third)
  • Has a raised 4th that adds brightness and tension
  • Common in film scores and jazz (especially over maj7#11 chords)
  • Creates a dreamy, otherworldly atmosphere

Usage

f_lydian = Scales[:et12][440.0][:lydian][65]
f_lydian.tonic  # F (65)
f_lydian.IV     # B (71) - augmented fourth (characteristic)

See Also:

Constant Summary collapse

@@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: 6 },
             { functions: %i[V _5 dominant fifth],
pitch: 7 },
             { functions: %i[VI _6 submediant 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 + 6 },
             { 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

Number of diatonic degrees.

Returns:

  • (Integer) —

    7



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# File 'lib/musa-dsl/music/scale_kinds/modes/lydian_scale_kind.rb', line 97

def grades
  7
end

.id ⇒ Symbol

Scale kind identifier.

Returns:

  • (Symbol) —

    :lydian



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# File 'lib/musa-dsl/music/scale_kinds/modes/lydian_scale_kind.rb', line 103

def id
  :lydian
end

.pitches ⇒ Array<Hash>

Pitch structure.

Returns:

  • (Array<Hash>) —

    pitch definitions with functions and offsets



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# File 'lib/musa-dsl/music/scale_kinds/modes/lydian_scale_kind.rb', line 91

def pitches
  @@pitches
end