music

The music gem provides a means on calculating notes and chords.

Examples:

All examples below assume that include Music has been called, though you can also use Music::Note, Music::Chord, etc...

Creating notes:

note = Note.new(698.46) # Creates a note object with the frequency 698.46
note = Note.new('F#6') # Creates an F sharp note in the 6th octave

Comparing notes:

Note.new(698.46) < Note.new(1975.53)    # => true
Note.new(698.46) == Note.new('F5')      # => true

Converting from frequency to note string and vice versa:

Note.new(698.46).note_string    # => 'F5'
Note.new('Bb3').frequency       # => 233.08

Find how many semitones two notes are apart:

Note.note_distance('A4', 'A#4')     # => 1
Note.note_distance('B1', 'F1')      # => -6
Note.note_distance('G#1', 'Ab1')    # => 0

Adjust frequencies by semitones:

Note.frequency_adjustment(440.0, 15)    # => 1046.50

Create chords:

chord = Chord.new(['C4', 'E4', 'G4'])   # Create a C major chord

Describe chords:

Chord.new(['C4', 'Eb4', 'Gb4'])     # => ['C', :diminished]

For further usage:

Use the term musical term 'interval' or 'semitones' instead of 'distance' in code
'C-' can be used to represent C minor
There can be many versions of chords. See: http://giventowail.com/lessons/evan/the-basics-major-minor-and-power-chords?phpMyAdmin=97715a053dab6cd797cf01c69d7492a4
Implement calculation of 'cents'

Contributions are welcome. Check out the issues list and feel free to fork and make a pull request if you have any fixes/additions.