Oh,
quiet over there, you...thing, you!

heheh
Yadayada like I didn't read you the first time. Now, whether software mixing was used in that version of DirectSound (1.4.x) I don't know, nor whether this is really even releated to the issue, but point being, just use a better NetPlay emulator. If and when zilmar puts NetPlay into Project64, according to some of the discussions on the beta forum, I think the team will have a good idea on how to release a NetPlay-supporting version of Project64 without this issue with Vista, but until then, use Mupen64k or 1964.