I did the buffer change, and still nothing... but until I went to:
Menu > Options > Aica > Mute CDDA
That's when it stopped.
The sound came back, and the buzzing went away.
I did change the buffer to 4096 however... but it was still buzzing until I muted the CDDA.
Maybe it requires both? Not sure, but didnt test. I am not a nullDC pro, nor know much about it... but it was a quick fix for me.