We have the same rig and I found that the TV audio out (on the TV itself) is sent directly to the RCA surround sound system. Change the input on the RCA to AUX IN and the TV will play thru the RCA. I found that if I turn the TV volumn down to a "2" then control the RCA volumn for a comfortable level that it works great. Also I set the "surround" to stereo and it sounds great.
I guess I should add that we have DirecTV. The box is located in the area under the TV and is connected to the TV via a HDMI cable.
2011 Georgetown 378TS in FireMist
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