Try turning your speakers/headphones down to 50% volume instead of 100%, increase the windows volume to compensate
That wouldn't account for the sound skipping...
My system runs the game just fine (Quad core, geforce 260 gtx, 4 gigs ram, vista64, X-Fi Extreme Music sound card...)
It is very obviously a problem with the game being in beta, but I'm wondering if it will be fixed. I do realize the game has a LOT of bugs left to iron out, so I'm still hopeful that it will be fixed in time for launch date, but the day of release is getting closer.