Hissing from audio on DTS-Master and DolbyHD

I am getting a terrible hissing sound on DolbyHD tracks and DTS-Matser tracks. When I change the audio to AC3 5.1 there is no problem. I am running the decoding via my receiver (DataSat RS20i) and have the audio set to "WASAPI RS20i" in XBMC. I checked to see if it was my reciever, but when I play through a bluray player DolbyHD and DTS plays fine.

So it is definitely XBMC. So does anyone know how to fix this?