"Some time ago, in the summer of 2001 if I recall correctly, I ran into an intriguing page at http://chaos.yerbox.org/face/ (Chaosmachine's more recent page can be found at blamcast.net). The original page, which sadly has since then disappered from the face of the earth, was all about this hidden "demon face" in one of Aphex Twin's tracks, #2 (the long formula) on "Windowlicker".
This face was supposed to be viewable with a spectrograph program, so I decided to try it myself. A spectrograph basically visualizes the sound spectrum.
First I needed to extract the track from the Windowlicker CD, which was easy with CDex. The extraction of the whole track was not really necessary because the "face" is situated at the very end of the track, starting from the 5:27 mark and lasting for about 10 seconds. There are other "audio images" on this particular track as well (and one at the end of the first track), but the face is certainly the most exciting of them all.
After I had the wav-file, I used a program called Spectrogram to visualize the file. To my amazement, it worked, and I was soon staring at the "demon" face:
While examining the image, I came to the conclusion that something was not right. So I started messing around with the settings of the spectrograph program, and after a bit of knob twiddling the mystery revealed itself: the face was supposed to be watched with a logarithmic frequency scale, not with a linear scale.
A linear scale provided the "demon face", but with a logarithmic scale the end results were quite different: "
There's more on the link. I thought it was pretty neat.
