The 5.1 comes from the built in mic on my camera. Amazon.com: Sony HDR-SR1 AVCHD 2.1 MP 30GB High-Definition Hard Disk Drive Camcorder with 10x Optical Zoom: Camera & Photo
I made holes in my ZoomCam enclosure so that it is more pronounced. (two up front, two on the sides, and the back is open. So you actually have spatial sound when listening to it on a system that can handle it. (I play mine back in my theater).
I'm having issues with blip only putting SOME of my videos in HD... I'm uploading my latest video for the second time tonight just on youtube so I can get it in HD.
It is a pain how all these systems don't work well together. Or they do for a while, then they change stuff, and you have issues.
As far as mounting, I like footage that is between your eyes. The way Akimbo Assassin does it is perfect, but you can't get an action cam like that easily... So the next best is right above your head, but between your eyes. (I put mine over my left eye, so my hopper on the right side doesn't block the shots).
I use the furnished tape mount that comes with the Roam, then I duct tape the back to keep it pointed up, and not moving around when you run.