ring-modulator

Here's a ring modulator implemented in just 22 lines of C.

Building

gcc ring.c -o ./ring

Using

./ring <inputfile> <modulation freq>
./ring input.raw 1000

Input File

To keep the code simple, you will need to convert your input file to a 48kHz/32-bit raw PCM. This is easy to do with SoX like this:

sox input.mp3 -c 1 -r 48000 -b 32 -e float -t raw input.raw

Output

This will output a 48kHz/32-bit raw PCM file called out.raw.

Playing back with SoX

play -c 1 -r 48000 -b 32 -e float -t raw out.raw