Hi Fortuner,
How are ya? Seems like you just bought new stuff
Unfortunately for you my friend I got some bad news. I'm assuming here that you want to record 5.1 audio to your DVR for television programs you want to watch?
Unless your DVR has a Digital Audio Input, it will not be able to record high definition audio. Sorry!
However, I've read a couple of findings and they say that there are known exceptions these days. Check this out:
Digital Audio Connections has 4 main types: Optical (using red LED), Coaxial (high grade coax with RCA connector), 6 channel (independant set of wires for each channel between devices), and Over HDMI cable (cannot separate audio/video). <<< It's impossible to convert any of these mediums to another via a cable. ALSO: If you are recording HD OTA via the coaxial input (using an ATSC Tuner), then your DVR will record the HD audio and HD video.