As noted in our iTunes 8 first look and review, iTunes 8 features a new default visualizer that many people--myself included--find much more visually interesting than the version in prior releases. As I noted in the First Look, after enabling the visualizer (View -> Show Visualizer or Command-T), you can call up its help screen by pressing the "?" key. On the help screen, you'll see that you can press M to change modes, P to change palettes, N to toggle nebula mode on and off, and much more.
But you won't find the following keys listed in help--these keys are left over from the days of yore, when the now-in-iTunes visualizer was an independent iTunes plug-in known as Magnetosphere. These hidden keys offer even more control over the behavior of the visualizer:
- + and -: Increase or decrease the intensity (brightness) of the particles; multiple presses further increase or decrease the intensity.
- A and S: Add or Subtract particles to the visualizer. You can make the visualizer as complex (or sparse) as you wish.
- R: Reset the intensity and particle count to their default values.
- E: When in nebula mode (press N), this greatly accentuates the nebula clouds, making them very easy to see. (If you've used the M key to change modes, you may find that the nebula clouds aren't visible; it seems they're only used in certain modes.)
There may be other commands that aren't covered in the help screen, but these are the only ones I've run across so far.