Caleb Madrigal

Programming, Hacking, Math, and Art

 

Pyknon Intro, Chords, and Intervals

I've continued on my (hopefully) short-term fascination with music+math (it's fun, but really bad for productivity). So I found this great library for generating music in Python called Pyknon. And it can be installed using pip: pip install pyknon.

I wrote a little python script just to help me understand some concepts in music theory like intervals and chords. It is meant to be read top to bottom (which is why I intersperse functions and variables throughout). It is NOT written in good modular form (in general, I don't recommend writing python like this). This code can also be used as an intro to the pyknon library.

Behold:

from pyknon.genmidi import Midi
from pyknon.music import NoteSeq, Note, Rest

####### First we'll generate ...

Music Theory and Math Notes

For the last day, I've done some reading on music theory (trying to understand why things are the way they are in terms of math). Here are my raw unedited notes:

Important musical ratios:

  • Unison: 1:1 frequency
  • Octave: 2:1 frequency
    • 12 semitone increase
  • Fifth: 3:2 frequency (i.e. multiply by 1.5)
    • 7 semitone increase
  • Semitone: 2^(1./12) (12th root of 2) - about 1.059 - this is the "half-step" distance, so you can multiply the frequency of F by 1.059 to get the frequency for F#

Scales and keys

  • Chromatic scale: 12 notes (list of all semitones in an octave)
  • Diatomic scale: 7 notes
  • To be in a "key" (like C-major) means to select 7 notes from the 12 notes in the ...