I made an adapter for outputting audio via your video card. VGA has three analog color wires, and each has its own ground/return. If you connect a 75 ohm resistor across one of them (generally green), the computer recognizes your "external monitor", and you're free to use Red/Red-return and Blue/Blue-return for audio.

Unfortunately, while video can handle a DC bias (e.g.: white screens), about 28% of the signal is dedicated to the horizontal and vertical sync (at 800 x 600) -- which is at ground. This means that if you scale audio from -1/+1 to 0-255 color intensity, you will get annoying hums at your refresh rate and horizontal sync rate. Instead, I just chopped off the bottom half of the audio signal.

Two apps are demoed: one for generating tones using ASCII values from the keyboard, and one for rendering a stereo audio file (the amen break) to Red/Blue components at 60 fps.

Bears some vague similarities to "Tempest for Eliza" erikyyy.de/tempest/

Watch the raw amen video here: vimeo.com/3293150