spis2022.github.io

SPIS 2022, Breadth 08/19 (Phill)

Basic concepts

• Sound is vibration
• Electronic sound is caused by driving a speaker with a voltage
  • There is some max and min voltage, which for convenience, we’ll represent as -1 and +1.
  • 0 means the speaker is at rest and silent.
  • -1 means it’s stretched all the way in one direction
  • +1 means it’s stretched all the way in the other
  • We need to avoid going past -1 or +1
  • So a sine wave is a convenient way to represent that.

Enabling Audio in a repl

To enable audio:

• On the ⋮ menu next to Files, click Show hidden files
• add audio = true as first line in the .replit file

audio = true

Demo of sound in a repl

https://replit.com/@PhillipConrad/audio-python-2#main.py

Attack, Decay, Sustain, Release

https://linuxaudio.github.io/libremusicproduction/html/answer/adsr-envelope.html

Sine wave to square wave

https://www.allaboutcircuits.com/textbook/alternating-current/chpt-7/square-wave-signals/

Demo of sound with Pure Python

https://github.com/spis2022/audio-plain-python

More resources

Some resources for sound/audio

Python-based (that do not depend on repl.it)

• Playing sound with basic python
  • This may not work in repl.it

Repl.it (Python-based)

• Enabling Audio in your repl
• Audio on repl.it [BETA] documentation
• Example Repl that plays sound
• wave, a library to create wave files with Python
• Tutorial: read and write .wav files using python wave library
• (python) replit api reference

Repl.it (non-Python)

• Making music with replit
  • Javascript based, but little to no Javascript knowledge needed

Advanced git/GitHub

This site is open source. Improve this page.