Sonos Arc via eArc with AVR

Thats pretty much it, yea. I can't see why it shouldn't work. Presumably running the Sky box or PS5 to to the TV via the AVR is no different to plugging it straight into the TV, with the TV's eARC then plugged into the Arc.

If the TV’s are using different resolutions, the receiver may not support this simultaneously.

No requirements for both to be on at the same time, and im pretty sure the AVR can support two totally independent outputs but I will check. It's a Yamaha RXA6A.

Supporting two independent outputs is easy if resolution and other settings match. If things do not match what I have seen on three different systems is that the source device negotiated the best common output settings so all connected could play.

Really ugly when your 4K big screen gets forced to 720 because you tried to add that old spare, small screen TV to watch in another room.

Yea that makes sense. But both screens will be very similar though, 4k 120hz+ etc. Reckon it should be a goer but will try and get my hands on someone's device to test it.

You are sure the second eARC on the receiver is an output?

Does the receiver's eArc capability have anything to do with it? Would it even need eARC? The receiver will be outputting audio and video via HDMI to one of the TV's HDMI inputs, that is all the receiver is doing, effectively passong through the source to the TV. The Sonos Arc will be connected to the TV's eARC enabled HDMI inputs, allowing the TV to pass the audio to the Arc via eARC, no?

Just as a note of caution, based on what I see on Yamaha’s information page, this device passes through eARC signal, but doesn’t create them. So the point 

• You want to connect a Sonos Arc to the TV via its HDMI-eARC

is especially important. 

Wouldn't it be the TV that creates the eARC signal? For example, what is the difference between the following two signals chains:

PS5 > TV (HDMI2) > TV(HDMI1 - eARC) > sonos Arc

Vs

PS5 > AVR > TV(HDMI2) > TV(HDMI1 - eARC) > sonos Arc?

Yes, the TV does. For Audio, there is no difference between those two, because the Sonos is connected to the TV directly.

For signals coming in, the TV doesn’t really care what device they’re coming from, only that it’s an HDMI signal. The CEC ‘electronics’ inside the TV takes the standard HDMI audio and reflects it to a different pin set back out via the ARC/eARC port to the Sonos. 

The CEC ‘electronics’ are responsible for communicating to each HDMI device what is connected, and what type of signals it can receive. The Sonos tells the CEC system several things. That it is an audio sink connected, what types of audio it can play, and what volume it has been set at. The CEC then passes whatever parts are necessary/appropriate to other devices that are connected via HDMI (that are CEC compliant). More information here. 

The key difference in your two examples is the insertion of an AVR. If that AVR doesn’t pass CEC data correctly, then the PS5 won’t get appropriate data from the CEC system in the TV (and ultimately from the Sonos). 

One of the challenges, I suspect, in many people’s thinking, is the inherent challenge of text, in which you express the connection linearly. As I would do, as well, no slight intended. In fact, the CEC system is more of a ‘hub’, which takes data from multiple HDMI (digital both ways, in and out, which is why CEC doesn’t work with optical) and then passes the appropriate data back to whatever device has been registered as needing ‘that data’. 

Sounds like i need to get hold of an Arc and give it a try before I buy. 

Sonos has a good try and return if not happy warranty. Watch the expiration date for your country!

CEC will likely get confused in this setup because there are two TV’s. You will probably need to install a CEC blocker to at least one of the TV’s.

You’re getting a lot of advice that mentions a lot of what if’s. At this point if you already have the Sonos components go ahead and try the connections. If not I’d start with a Beam 2 as it’s smaller and cheaper to run a test. If the test fails to work just return. 

With CEC Blockers(s) installed, since there is no need for simultaneous TV operation, this will work, but it might be a little clumsy to operate.