Ben Daglish > Music-Scales-0.07 > Music::Scales

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Module Version: 0.07   Source  

NAME ^

 Scales - supply necessary notes / offsets for musical scales

SYNOPSIS ^

    use Music::Scales;

    my @maj = get_scale_notes('Eb');           # defaults to major
    print join(" ",@maj);                      # "Eb F G Ab Bb C D"
    my @blues = get_scale_nums('bl');          # 'bl','blu','blue','blues'
    print join(" ",@blues);                    # "0 3 5 6 7 10"
    my %min = get_scale_offsets ('G','mm',1);  # descending melodic minor
    print map {"$_=$min{$_} "} sort keys %min; # "A=0 B=-1 C=0 D=0 E=-1 F=0 G=0"

DESCRIPTION ^

 Given a keynote A-G(#/b) and a scale-name, will return the scale, 
 either as an array of notenames or as a hash of semitone-offsets for each note.

METHODS ^

get_scale_nums($scale[,$descending])

returns an array of semitone offsets for the requested scale, ascending/descending the given scale for one octave. The descending flag determines the direction of the scale, and also affects those scales (such as melodic minor) where the notes vary depending upon the direction. Scaletypes and valid values for $scale are listed below.

get_scale_notes($notename[,$scale,$descending,$keypref])

returns an array of notenames, starting from the given keynote. Enharmonic equivalencies (whether to use F# or Gb, for instance) are calculated based on the keynote and the scale. Basically, it attempts to do the Right Thing if the scale is an 8-note one, (the 7th in G harmonic minor being F# rather than Gb, although G minor is a 'flat' key), but for any other scales, (Chromatic, blues etc.) it picks equivalencies based upon the keynote. This can be overidden with $keypref, setting to be either '#' or 'b' for sharps and flats respectively. Cruftiness abounds here :)

get_scale_offsets($notename[,$scale,$descending,$keypref])

as get_scale_notes(), except it returns a hash of notenames with the values being a semitone offset (-1, 0 or 1) as shown in the synopsis.

get_scale_MIDI($notename,$octave[,$scale,$descending])

as get_scale_notes(), but returns an array of MIDI note-numbers, given an octave number (-1..9).

get_scale_PDL($notename,$octave[,$scale,$descending])

as get_scale_MIDI(), but returns an array of PDL-format notes.

is_scale($scalename)

returns true if $scalename is a valid scale name used in this module.

SCALES ^

Scales can be passed either by name or number. The default scale is 'major' if none / invalid is given. Text::Abbrev is used on scalenames, so they can be as abbreviated as unambiguously possible ('dor','io' etc.). Other abbreviations are shown in brackets.

  1 ionian / major / hypolydian
  2 dorian / hypmixolydian
  3 phrygian / hypoaeolian
  4 lydian  / hypolocrian
  5 mixolydian / hypoionian
  6 aeolian / hypodorian / minor / m
  7 locrian / hypophrygian
  8 harmonic minor / hm
  9 melodic minor / mm
 10 blues 
 11 pentatonic (pmajor)
 12 chromatic 
 13 diminished 
 14 wholetone 
 15 augmented 
 16 hungarian minor 
 17 3 semitone 
 18 4 semitone 
 19 neapolitan minor (nmin)
 20 neapolitan major (nmaj)
 21 todi 
 22 marva 
 23 persian 
 24 oriental 
 25 romanian 
 26 pelog 
 27 iwato 
 28 hirajoshi 
 29 egyptian 
 30 pentatonic minor (pminor)

EXAMPLE ^

This will print every scale in every key, adjusting the enharmonic equivalents accordingly.

        foreach my $note qw (C C# D D# E F F# G G# A A# B) {
        foreach my $mode (1..30) {
            my @notes = get_scale_notes($note,$mode);
            push @notes, get_scale_notes($note,$mode,1); # descending
            print join(" ",@notes),"\n";
        }
    }

TODO ^

 Add further range of scales from http://www.cs.ruu.nl/pub/MIDI/DOC/scales.zip
 Improve enharmonic eqivalents.
 Microtones
 Generate ragas,gamelan etc.  - maybe needs an 'ethnic' subset of modules

AUTHOR ^

 Ben Daglish (bdaglish@surfnet-ds.co.uk)

 Thanks to Steve Hay for pointing out my 'minor' mix-up and many suggestions.
 Thanks also to Gene Boggs for the 'is_scale' suggestion / code.

BUGS ^

 A few enharmonic problems still...

 All feedback most welcome.

COPYRIGHT ^

 Copyright (c) 2003, Ben Daglish. All Rights Reserved.
 This program is free software; you can redistribute
 it and/or modify it under the same terms as Perl itself.

 The full text of the license can be found in the
 LICENSE file included with this module.

SEE ALSO ^

PDL::Audio::Scale, perl(1).

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