This is exactly the reason I'd like to see the "beep" replaced by a generic keyclick. The point is to indicate to the user that their keypress has been recognised.
I put a patch up at http://www.rockbox.org/tracker/task/7307, but it needs resyncing. There didn't seem to be much interest it the idea at the time (i.e. it's felt worth committing), but I'll revisit if others think it's useful. I certainly do! I suspect that stopping playback to improve perceived responsiveness probably wouldn't respond as quickly as you'd like anyway. -- pondlife
