Class: Musa::Scales::TwelveSemitonesScaleSystem Abstract

Inherits:
ScaleSystem show all
Defined in:
lib/musa-dsl/music/equally-tempered-12-tone-scale-system.rb

Overview

This class is abstract.

Subclasses must implement ScaleSystem.frequency_of_pitch

Base class for 12-semitone scale systems.

TwelveSemitonesScaleSystem provides the foundation for any scale system using 12 semitones per octave. It defines intervals and structure but doesn't specify tuning (frequency calculation).

Concrete subclasses must implement frequency calculation:

Intervals

Defines standard interval names using semitone distances:

{ P0: 0, m2: 1, M2: 2, m3: 3, M3: 4, P4: 5, TT: 6,
  P5: 7, m6: 8, M6: 9, m7: 10, M7: 11, P8: 12 }

See Also:

Direct Known Subclasses

EquallyTempered12ToneScaleSystem

Constant Summary collapse

@@intervals = 
{ P0: 0, m2: 1, M2: 2, m3: 3, M3: 4, P4: 5, TT: 6, P5: 7, m6: 8, M6: 9, m7: 10, M7: 11, P8: 12 }

Class Method Summary collapse

Class Method Details

.id ⇒ Symbol

System identifier.

Returns:

  • (Symbol) —

    :et12



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# File 'lib/musa-dsl/music/equally-tempered-12-tone-scale-system.rb', line 31

def id
  :et12
end

.intervals ⇒ Hash{Symbol => Integer}

Interval definitions.

Examples:

intervals[:P5]  # => 7 (perfect fifth)
intervals[:M3]  # => 4 (major third)

Returns:

  • (Hash{Symbol => Integer}) —

    interval name to semitones mapping



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# File 'lib/musa-dsl/music/equally-tempered-12-tone-scale-system.rb', line 54

def intervals
  @@intervals
end

.notes_in_octave ⇒ Integer

Number of distinct notes per octave.

Returns:

  • (Integer) —

    12



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# File 'lib/musa-dsl/music/equally-tempered-12-tone-scale-system.rb', line 37

def notes_in_octave
  12
end

.part_of_tone_size ⇒ Integer

Size of smallest pitch division.

Returns:

  • (Integer) —

    1 (semitone)



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# File 'lib/musa-dsl/music/equally-tempered-12-tone-scale-system.rb', line 43

def part_of_tone_size
  1
end