Quick C program to mangle a WAV file
Takes a mono WAV file, PCM encoded, 16 bit signed sample at 16000 samples per second and outputs a delayed version, where the delay varies according to a sine function
gcc mangle.c -o mangle -lm
./mangle test.wav out.wav 100
includes two sample WAV files. Use something like Goldwave to listen to them, or record others.