Jack or Tradez and then Rich wrote:

...

And what is "orbit sound options" ?

This is only in the DOS version currently; it plays a frequencies based on the orbit values as the orbit is computed.

You get to the parameter screen with Ctrl+F in the DOS version.

(I'm back from vacation, been out of touch more than a week.) Here's a bit of history. One day out of the blue a blind fellow started corresponding with the developers. The upshot was we added the sound feature that allows a blind person (or anyone interested in fractal music) to visualize fractal orbits. Our correspondent was excited about it and said it really helped him understand fractals. One year at SIGRAPH I heard a talk about fractal music. Highly correlated sounds and random sounds are equally uninteresting; but semi-correlated sound is interesting. The semi-correlated type is called "1/f noise". As a pixel progesses acorss the screen, the orbits evolve, and when converted to music, can have an uncanny resemblance to a "composed" piece of music, with the same theme repeated, but changed somewhat each time. Bill Jemison (I believe) has done a lot with this. I am sure few people use the sound feature. However those that do really need it (e.g. the blind) or really use it creatively (e.g. Bill J.) Tim