from the readme...
song04 generates an ambient soundscape of detuned sine waves. the sine waves are clustered together at specific frequencies, with their exact characteristics determined by the input file s4_param.txt. the output can be written to a file, directly to audio output, or both simultaneously (with some serious performance degradation).
song04 can generate a maximum of 1024 sine waves. on modern PCs, it is possible to generate approximately 200 sine waves and play them back live (tested on a 1.6GHz core 2 duo and a 3.0 GHz celeron). if your computer is slower, the output may glitch and it may also be difficult to regain control of your PC. keep hitting Ctrl-C until song04 is killed. if this happens, try reducing the number of sine waves or render your output to .wav. rendering a full 1024 sine waves is time consuming, but the output can be quite pretty.
this project came out my work writing music for the ADSP-218x DSPs. this song is a generalization of one of the first songs i made for a DSP. it's nice and interesting and fun to modify parameters to see what the output will sound like. it's edutainment!
song04 is designed to run at the command prompt (aka a DOS box). to launch a command prompt, double-click on the shortcut called "song04-cmd" in the directory where the contents of song04.zip were unzipped. double-clicking song04.exe directly won't do anything other than output help and immediately exit.
download song04 here.