The Beam and the TX-L20D are a country mile apart in terms of what they'll do. Of course the Onkyo is going to take a little longer to set up and get right for you. That's the point. For. You. But once you have done it in the way that works for you, then the Onkyo should respond to TV volume commands and accept sound routed via the TV.
I'm not sure exactly what what you mean by "how do I change my other devices ? Apple TV being one of them" Are you talking about enabling HDMI CEC or switching to the sources? The answer for either is in the manuals for the products. Go online and seek advice on the Apple product. Read the Onkyo manual for TX-L20D-related issues.
I'm not sure exactly what what you mean by "how do I change my other devices ? Apple TV being one of them" Are you talking about enabling HDMI CEC or switching to the sources? The answer for either is in the manuals for the products. Go online and seek advice on the Apple product. Read the Onkyo manual for TX-L20D-related issues.