idmtheory 0.1.0

A module for music theory concepts including tone intervals, notes, scales and chords.

IDMTheory

IDMTheory is a python module with functions and data to support building of music theory applications.

The Current State of IDMTheory

IDMTheory is currently in beta version.

What's IDMTheory?

Notes and Intervals

In IDMTheory, notes are represented by an integer type. Note value 0 corresponds to the C note in the first octave. Each positive integer step from 0 represents a semitone step in the chromatic scale.

Note names can use the note name style 'flat' or 'sharp'. Flat notation uses the 'b' character to indicate a flattened note (e.g. 'Gb') while sharp notation uses the '#' character to indicate a shapened note (e.g. 'F#').

The following note intervals are defined:

• IDToneInterval.TONIC = 0
• IDToneInterval.SEMI_TONE = 1
• IDToneInterval.TONE = 2 * SEMI_TONE
• IDToneInterval.MINOR_2ND = 1 * SEMI_TONE
• IDToneInterval.MAJOR_2ND = 2 * SEMI_TONE
• IDToneInterval.MINOR_3RD = 3 * SEMI_TONE
• IDToneInterval.MAJOR_3RD = 4 * SEMI_TONE
• IDToneInterval.PERFECT_4TH = 5 * SEMI_TONE
• IDToneInterval.DIMINISHED_5TH = 6 * SEMI_TONE
• IDToneInterval.AUGMENTED_4TH = 6 * SEMI_TONE
• IDToneInterval.TRITONE = 6 * SEMI_TONE
• IDToneInterval.PERFERCT_5TH = 7 * SEMI_TONE
• IDToneInterval.AUGMENTED_5TH = 8 * SEMI_TONE
• IDToneInterval.MINOR_6TH = 8 * SEMI_TONE
• IDToneInterval.MAJOR_6TH = 9 * SEMI_TONE
• IDToneInterval.MINOR_7TH = 10 * SEMI_TONE
• IDToneInterval.MAJOR_7TH = 11 * SEMI_TONE
• IDToneInterval.PERFECT_OCTAVE = 12 * SEMI_TONE
• IDToneInterval.MINOR_9TH = 13 * SEMI_TONE
• IDToneInterval.MAJOR_9TH = 14 * SEMI_TONE
• IDToneInterval.PERFECT_11TH = 17 * SEMI_TONE
• IDToneInterval.MAJOR_13TH = 21 * SEMI_TONE
• IDToneInterval.OCTAVE = PERFECT_OCTAVE

A set of functions and range transforms can be used to manipulate notes, for example:

• tone_interval_short_name
• normalize_tone_intervals
• transpose_tone_intervals

Chords

The class IDChord represents a chord. A chord is defined by:

• Its tonic note.
• Its IDChordType: MAJOR, MINOR, DIMINISHED or AUGMENTED.
• A set of chord modifiers (aka flags), for example 'Dominant 7' or 'Major 7'.

The following chord modifiers are available:

• IDChordFlags.DOMINANT_7
• IDChordFlags.MAJOR_7
• IDChordFlags.DOMINANT_9
• IDChordFlags.DOMINANT_11
• IDChordFlags.DOMINANT_13
• IDChordFlags.ADD_2
• IDChordFlags.ADD_6
• IDChordFlags.ADD_9
• IDChordFlags.FLAT_5TH
• IDChordFlags.SUSPENDED_2ND
• IDChordFlags.SUSPENDED_4TH

Chord modifiers can be combined, e.g. IDChordFlags.DOMINANT_7 | IDChordFlags.ADD_9 gives a 7+9 chord.

The class IDChordDatabase can be used to create a database with thousands of different chords. The database can be used to find which chord(s) a certain intervals of notes represent, or chords that a similar to each other.

Scales

The class IDScale can be used to define a specific note scale. Available scales are:

• Diatonic scales:
  • Natural Major
  • Dorian
  • Phrygian
  • Lydian
  • Mixolydian
  • Natural Minor
  • Locrian
• Harmonic scales:
  • Harmonic Minor
  • Locrian Natural 6
  • Major Augmented
  • Ukrainian Dorian
  • Phrygian Dominant
  • Lydian Natural 2
  • Super Locrian bb7
• Melodic scales:
  • Melodic Minor
  • Dorian b6
  • Lydian Augmented
  • Lydian Dominant
  • Mixolydian b6
  • Locrian #2
  • Super Locrian