Pioneer Elite vsx-33 sounds hollow with streaming content

I recently "upgraded" an older Sony ES 5.1 receiver in my family room to a Elite VSX-33 9.1 with HDMI support. The thing is, most streamed content (which in this room is 95% of the content watched) sounds hollow at best. When my OPPO BDP-83 is playing content, the THX settings on the receiver produce great sound. In a perfect world, all video from all sources would be of the highest quality, but in an imperfect source world, ( Netflix, HBO GO, MKV's ) how can I expand the soundfiled for a more rich experience. The Sony had a couple of settings I used to "virtualize" or expand the sound. (virtual 5.1 setting for instance)- it would do it's best to send some sort of signal to all speakers to produce a pseudo surround sound in the absence of a true surround source.