Okay so I'm pondering ordering a ROKU box. I just upgraded our cable modem and router to wireless-N and want to stream Amazon free prime videos to our plasma. Currently, my antenna box uses an optical cable to my receiver which allows me Dolby 5.1 on digital broadcast TV...the optical cable allows for the subwoofer channel. My concern is that I believe I only have one optical port which my antenna box uses. Will the ROKU send the Dolby 5.1 over the HDMI cable or will I need to hook the ROKU to my receiver with an HDMI cable -and- an optical cable? Thanks!