Setting CPU governor to "on demand" fixes the crackling problem.
In relation to the Siyah kernel and it's sound improvements - the headphone amp and stereo expansion settings definitely help (I wonder does the stereo expansion compensate for the stereo crosstalk?), the bass enhancement settings sound truly awful, and the DAC direct and 128x sampling don't make any difference to my ear. I was interested to see that TotallydubbedHD thought exactly the same. Still worth using in the wait until Voodoo, which should have working 128x sampling and DAC direct modes and sound even better, which will be AWESOME.
What does DAC direct mode mean? Is it about outputting digital audio to an external DAC? Or tweaking the internal DAC's settings (like the 128x sampling you mentioned).
Or is it something like this? (found by googling, though I don't really understand it...yet)
Edited by analogue 3 - 7/7/12 at 12:22pm