Class: Musa::Scales::PentatonicMajorScaleKind

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

Overview

Major pentatonic scale kind.

PentatonicMajorScaleKind defines the major pentatonic scale, a five-note scale derived from the major scale by omitting the 4th and 7th degrees. It has a bright, open sound and is extremely common in folk, rock, and blues.

Pitch Structure

5 diatonic degrees plus extended (6th-10th):

Scale Degrees (Roman numerals, uppercase for major):

  • I (tonic): Root (0 semitones)
  • II (supertonic): Major second (2 semitones)
  • III (mediant): Major third (4 semitones)
  • V (dominant): Perfect fifth (7 semitones)
  • VI (submediant): Major sixth (9 semitones)

Relationship to Major Scale

Major pentatonic = Major scale minus 4th and 7th degrees. This removes all semitone intervals, creating a scale with no dissonance.

Musical Character

The major pentatonic:

  • Has a bright, happy, open quality
  • No semitones = no tension or dissonance
  • Universal across cultures (found in music worldwide)
  • Common in folk, country, rock, pop, and blues

Usage

c_pent = Scales[:et12][440.0][:pentatonic_major][60]
c_pent.tonic     # C (60)
c_pent.dominant  # G (67)

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[V _4 dominant fourth],
pitch: 7 },
             { functions: %i[VI _5 submediant fifth],
pitch: 9 },
             { functions: %i[VIII _6 sixth],
pitch: 12 },
             { functions: %i[IX _7 seventh],
pitch: 12 + 2 },
             { functions: %i[X _8 eighth],
pitch: 12 + 4 },
             { functions: %i[XII _9 ninth],
pitch: 12 + 7 },
             { functions: %i[XIII _10 tenth],
pitch: 12 + 9 }].freeze

Class Method Summary collapse

Constructor Details

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

Class Method Details

.grades ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_major_scale_kind.rb', line 81

def grades
  5
end

.id ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_major_scale_kind.rb', line 85

def id
  :pentatonic_major
end

.pitches ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_major_scale_kind.rb', line 77

def pitches
  @@pitches
end