Is the static constant? If so, perhaps your issue has less to do with the crackling sound issue. If not perhaps the latency is peaking but not being captured by the tool - idk.
Haha probably not! I used to dabble a bit with DirectX programming, but that was before DirectX 10 and they changed many things including the audio architecture (probably due to DirectShow's poorly designed, easily broken codec 'merit' system imo.). Apparently post Vista, DirectX is using software mixers! (OMG!!! see:
http://en.wikipedia.org/wiki/Technical_features_new_to_Windows_Vista#Audio_stack_architecture), but Windows 8 has re-introduced it. [OpenAL anyone

]
Reminds me of the day Microsoft broke Windows Media Player back in the 90's - long time ago was it 7 or 8? I vaguely recall spotting that the wma decoder was a newer file, but had a lower version number than the one in the previous media player. The result - the old file was kept and media player broke. Coincidently Microsoft re-structured the architecture in the next release.
PS. I wonder if the hotfix mentioned on that page has anything to do with it -
perhaps try some other sample rate settings?