why can't I edit my last post anymore?
I'm sorry to be bumping an old thread, but I couldn't find any more recent discussions on this issue. Just now I got myself a Clip+ and installed the latest stable RB (3.12) and I'm having the same issues. Basically the original firmware has this constant helicopter-like noise while playing files, and RB is silent except for rather loud noise when accessing either internal storage or external SD card. Has any solution been found yet? I'd be prepared to do some detailed recordings together with spectrograms of all the different noises, if anyone is interested.
I don't think a solution exactly is possible, since its just a hardware problem with a smallish number of players. Probably the best you could try to do would be to shrink the size of the rockbox audio buffer so that it has to frequently refill like the sandisk firmware does. That said, I have no idea how well that would work (or even if rockbox will run with a small enough audio buffer for that to make a difference).