Syllabus 20091006
Tue Oct 6, 2009
- Review Command-line imagemagick assignment from last week
- "Audio Loops" Intro / "Hands-on" digital audio
Audio loops & "cat" ups
Check out the sox cookbook page.
Create your tones
Start by using sox to generate some "building block" sounds.
Convert each sound to a "raw" file to be manipulated by Python.
sox source.wav --rate 44100 --bits 16 --channels 2 --encoding signed-integer source.raw
Use Python Loops as a "Sequencer"
from os import system
for i in range(3):
system("cat 01.raw >> song.raw")
system("cat 03.raw >> song.raw")
system("sox --rate 44100 --bits 16 --channels 2 --encoding signed-integer song.raw song.wav")
system("rm song.raw")
system("play song.wav")
Example of "sequential loops":
from os import system
for i in range(3):
system("cat 01.raw >> song.raw")
system("cat 03.raw >> song.raw")
for i in range(3):
system("cat 02.raw >> song.raw")
system("cat 04.raw >> song.raw")
system("sox --rate 44100 --bits 16 --channels 2 --encoding signed-integer song.raw song.wav")
system("rm song.raw")
system("play song.wav")
Example of a "nested loop":
from os import system
for i in range(3):
system("cat 01.raw >> song.raw")
system("cat 03.raw >> song.raw")
for i in range(3):
system("cat 02.raw >> song.raw")
system("cat 04.raw >> song.raw")
# print("goodbye")
system("sox --rate 44100 --bits 16 --channels 2 --encoding signed-integer song.raw song.wav")
system("rm song.raw")
system("play song.wav")
Finding open-licensed audio online
- LibriVox is a site that encourages volunteers to record spoken-language versions of open-license texts (drawn from Project Gutenberg), Multilingual
- The Internet Archive has sections for audio and live music.
- The Freesound Project is a collaborative database of Creative Commons licensed sounds. Freesound focusses only on sound, not songs.
Assignment for next week
Produce a "song" using sox & python loops. Produce two "songs", one with "sequential loops", and one with a nested loop.