The keyboard is not used like it is in a regular dialog with the tab key switching between the different controls. The tab key method is good for filling out forms, like your name and address, but synthesizer parameters are not normally programmed in a particular order like a form is, so the tab key doesn't work very well. I decided that the arrow keys would make the most sense, so that is how I implemented keyboard navigation. The problem with doing it that way is that some of the controls ordinarily use the arrows keys to select values, like combo boxes and scroll bars. So, I rigged up the six editing keys above them to make up for this.
I've taken the liberty of redefining the meaning of a few keys, which might make it strange at first, but I think it makes sense tactilely.
The rules are pretty simple: for the six editing keys, the top three keys increase the value and the bottom three keys decrease it.
The arrow keys are the same in that they move the cursor in a certain direction, the only difference is that they move it from control to control.
An exception is with text controls, like the voice name, the left and right arrow keys will move the cursor left and right within the control, but if you use the right arrow key to move the cursor, it will eventually be moved out of the control and onto the control to the right. The left arrow key will return it to the text control.