SoX

sox (Sound Exchange) is a handy command line tool for generating, manipulating, and applying simple filters to audio.

Synthesis

sox -c1 -r8000 -n -t wav - synth 0.25 sine 220 vol 0.7 > beep.wav
sox -c1 -r8000 -n -t wav - synth 0.25 sine 220-440 vol 0.7 > sweep_up.wav
sox -c1 -r8000 -n -t wav - synth 0.25 sine 440-220 vol 0.7 > sweep_down.wav
sox -c1 -r8000 -n -t wav - synth 0.25 noise vol 0.7 > ch.wav
sox -c1 -r8000 -n -t wav - synth 2.0 sine 220-1000 vol 0.7 > sweep_up_long.wav
sox -c1 -r8000 -n -t wav - synth 2.0 sine 1000-220 vol 0.7 > sweep_down_long.wav

sox -c1 -r8000 -n -t wav - synth 0.5 square 330 vol 0.7 > bleep.wav

Working with "raw audio"

Working with raw files allows audio to get appended together; here sox is used to take a bunch of wavs, make them raw, send them all to stdout, the repackage them as a wav file.

(for file in *; do sox "$file" -t .raw -r 44100 -sw -c 2 -; done) | \
  sox -t .raw -r 44100 -sw -c 2 - -t .wav newfile.wav

source: [1]

Resources

• http://sox.sourceforge.net/
• Transform your audio files with sox]