Yes, that was my first suggestion. In the event that you cannot transfer audio via HDMI, you can always use the other audio interfaces (optical, analog).
It's not relly that your TV and AVR are not compatible, it is more like one of them does not support ARC.
Anyway, an optical cable should solve the issue.
Ah, sorry I worded that so awkwardly. I also didn't catch the "optical" in your first reply!
It works nicely. Thanks for your help!