This list is oriented towards a linux-based system, but many of these solutions are platform independent. The shared mathematical underpinning between music and computers goes beyond simple harmonics or even the complex mathematical systems underlying a Bach fugue. All music can technically be described as pink noise, where the spectral power distribution is proportional to the inverse of the frequency - there is the same amount of power between 1 Hz and 2 Hz as between 1,000 Hz and 2,000 Hz. Fractal Music attempts to create music automatically by exploiting this relationship. The samples are in the .au format, which can be played with most browsers.
Software is available for download, which allows PC users to create their own fractal music.
As stereo sound reproduction is commonplace, this allows for an additional channel to realize virtual spaces, although headphones are generally needed to avoid distortions introduced by loudspeakers' own spatial positions. Computer game designers and human interface specialists are particularly interested in developing 3d sound. Northwestern University provides useful background resources, with a primer that describes the physiology of 3d sound perception and some of the techniques used to reproduce it. Intended for the blind, the system can also be used in a wearable version. The software is compatible with USB video cameras and can handle general bitmaps as well.