Okay. so i have a very old denon avr receiver which does not have any hdmi ports. However, it does have an optical port. I have an asus sound card which has an optical port as well. I hooked it up to each other, and plugged in one of the speakers into the AVR, but cannot seem to get any sound coming from it. I have set the S/PDIF as the default on my computer, but nothing is coming from the speaker