I have an Onkyo HT-S5100 and I am I connected my TV to the receiver via an HDMI cable. Now I get video but no audio. I notice in the setup diagrams they show both a HDMI connection as well as stereo audio out from the tv to the receiver. Do I really need a stereo or digital out from the TV? shouldn't the HDMI be enough? Trying to get this going before SEC championship so please help soon!