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I have a Samsung home cinema (HT-D5530) which has ARC and a Samsung 3DTV (D6530) which has the same. I have an xbox 360 connected using HDMI and when i'm gaming I use the home cinema for surround sound but the sound keeps going off from time to time. It doesn't happen if I use an optical cable from the xbox to the cinema but it does when I switch ARC on.

The cinema works fine while watching movies or listening to cd's. It only seems to have the problem when the xbox is on but as I said, it works fine using an optical cable but as soon as I enable ARC then the sounds goes off every now and then.

What could be causing the problem ?. Thanks for all or any advice.