Cable the Amp to the Arc (preferred) (or to the router) and also Cable the Arc direct to your router aswell and see if that works for you.

Thanks for the quick reply @Ken_Griffiths. I’ve cabled the amp to the arc, but I’ve read that doesn’t work if ARC unless it’s in “wired” mode… but if I switch to that it wont be a part of home network anymore. 

Your devices will run on SonosNet - is there a particular reason that may cause you an issue?

All products will be on the same LAN subnet, accessible via your network, so your mobile controller devices and their Apps (running on your WiFi) will still be able to access all your Sonos devices.

Its worthwhile however setting the SonosNet channel 5+ channels away from your routers 2.4Ghz channel as that will reduce interference. I would also ‘fix’ the router to use a non-overlapping 2.4Ghz channel …and (optional) if you want to go even further, set the channel-width on that band to 20MHz.

@Ken_Griffiths

Its worthwhile however setting the SonosNet channel 5+ channels away from your routers 2.4Ghz channel as that will reduce interference. I would also ‘fix’ the router to use a non-overlapping 2.4Ghz channel …and (optional) if you want to go even further, set the channel-width on that band to 20MHz.

I believe the hinderance to the SonosNet is that the Arc doesn’t seem to reach the Amp with the SonosNet signal it’s putting out. I tried moving it closer (about 10 ft), but it’s still inside where the Arc is outside, and sitting on a stone mantle. 

I have a CAT6 cable running from the arc to the amp, but that doesn’t seem to help. Would you suggest I run CAT6 from both products to my internet router in order for them to truly connect?

As you already have the wired link between the Amp and Arc I would just cable the Arc to the router.

Note the Arc will be ‘controlling/distributing; the audio to the ‘bonded’ Amp/surrounds so no point linking that directly back to the router, just leave it as is, wired to the Arc.

@Ken_Griffiths Thanks again for the reply. 

With the existing cabled connection from the ARC to the Amp, the Setup function doesn’t work. It gives me the “check the product’s power & network” error. 

Let me backtrace my steps: 

1. Arc is set up correctly and working underneath TV. The HDMI ARC cable runs from the TV to the ARC itself. All is well. 
2. With the network cable unplugged, The Amp is set up as it’s own “room” and powers the outdoor speakers just fine. 
3. This is where I get stuck. I plug in the network cable from the ARC to the Amp, and then follow the dialogue to set up the Amp as Surrounds, but it won’t complete the set up. I get the error. If I try the same thing without the cable set up (as it’s intended design), I get an error. 

Even though this (below link) is in relation to the older Connect:Amp, in your case the same thing applies as the Amp, you say, is too far away for the wireless connection to the Arc. So you need one device wired to the router, my suggestion is to just wire your Arc back to the router and leave the Amp wired to the Arc and it should then work … perhaps see this document:

https://support.sonos.com/s/article/2237

@Ken_Griffiths I got it working!! (I think)

So, the solution right now:

1. Both the amp and arc have to start set up as separate rooms. 
2. I connected the Arc to the Amp via a Cat6 cable. 
3. I also connected the Amp to my router with another Cat6 cable. 
4. That’s when they finally “magically” connected the Amp as surrounds. 

Now, I still don’t have the amp speakers pushing out audio because I haven’t been able to complete the TrueTune step (there’s a lot of background noise outside).. either that or there’s some configuration I haven’t quote tinkered with yet. Both are still set with “wifi on” 

The TruePlay tuning only works if you are using the Sonance architectural speakers shown in this link…

https://www.sonos.com/en-us/shop/architectural
 

Try playing a 5.1 audio source to the room and also set the surrounds to play ‘Full’ music audio rather than ‘ambient’. To change that setting goto ‘Settings/System/tArc Room Name]/Surround Audio” and see if that works for you.

For anyone who may see this in the future: 

I finally got everything configured the way it’s intended to work!

1. My HDMI ARC cable is plugged into the back of my ARC. 
2. The ARC needed to be wired to the AMP using Cat6. 
3. The AMP also needed to be wired to my router using a Cat6 cable. 
4. The AMP speakers need to be set up as a separate room before trying to set them up as Surrounds to the Arc. 
5. I had to “disable” wifi on both the Arc and Amp to get the Surround setup complete. 
6. After set up, I had to make sure the TV was configured to push out Dolby and it’s internal TV speakers set to “off”. 
7. On my Apple TV, I had to go into it’s own Audio Settings, make sure it’s pushing out Dolby and then, (this is KEY), select the Sonos Room of Arc+Amp as the default speaker AND unselect the TV speakers… otherwise it only pushes audio to the Arc. 

Hallelujah. 

On your Apple TV?  That sounds like you’re using Apple airplay to send the audio rather than the HDMI-ARC connection between the TV and Sonos arc.  

@Alex Morrison

I agree with Danny, it looks like the ATV is using Airplay to send the audio to the speakers - Once devices are ‘bonded’ as a HT setup it should just show as one ‘Room’ too (whatever Room your Arc is named).

Also, whilst I assume you have your own reasons, however in most use-cases, there is rarely the need to cable the Arc, or the Amp, back to the router - that wired setup is only needed for the older Connect:Amp, which did not have a 5Ghz wireless adapter - the new Amp has a 5Ghz adapter and so can happily ‘bond’ to the Arc over WiFi, unless of course it’s located a fair distance away from the Arc, behind a brick wall, or two, but it’s not normally going to be a ‘typical’ HT setup for others.

edit: I think it’s worth users first considering trying to move the Amp closer to the HT device instead, if they can possibly achieve that.

@Ken_Griffiths Right. There is an exterior brick wall in between the Arc & Amp.. plus the Arc sits on top of a stone mantle, so they were never able to connect via their own 5G subnet. 

They are bonded and set up as a single room now, but will only stay bonded via the hardwire. 

Going back to the Airplay discussion - I’ll take a look tonight, but I could’ve sworn it’s just a default “select speaker” option in the Apple TV settings that I changed. Before I changed that, audio would only come through the Arc and not the amp as well. 

@Alex Morrison, 

Just to let you know, that my understanding is, in the widely available ‘public beta’ of tvOS, Apple seemed to have somewhat improved the way the default audio-out to a TV/Receiver is now selected on their ATV device, as there has apparently been some slight confusion in the past over the HDMI connection and those speakers available over Airplay.

IIRC the usual selection on the current v14.7 of tvOS is to select "HDMI” or wording similar to that  - but that’s from memory only and I’m not near my system to be able to check those settings for you.. but it’s worth just checking what you have selected in the ATV settings.

As far as I’m aware, AirPlay 2 can not send a Dolby Digital signal to a Sonos device, only a stereo signal. 

Just to clarify further, my understanding is that an Apple Device can send a 5.1 (Dolby Digital) signal to the Apple TV via AirPlay 2.But the signal being sent from an Apple device (the Apple TV in this case) can only send a stereo signal via AirPlay 2 to the Sonos. 

That’s my understanding. AirPlay 2 restricts Dolby Digital to between Apple devices, not Apple devices get only a stereo signal.

Happy to be corrected if my understanding is wrong. 

Shoot. Y’all were right.

When I go to ATV’s audio settings, I can only select the Sonos room in the “temporary audio output”. The only default is “TV speakers” (which do push out to the ARC, but a signal is not reaching the amp surrounds)

I’m stuck again!

ATV outputs using LPCM codec by default (which the Sonos Arc does support by the way), but perhaps the connected TV will not ‘pass through’ that codec. What TV make/model is the ATV connected to?

If you goto the ATV "Settings/video and audio” what output do you get if you select the audio format and switch on the ‘change format’ option and turn off the auto option - just see if changing that setting then works for you.

Tv model:

SunbriteTV Veranda (2nd gen) 4K UHD HDR LED 55”

The “audio format” was set to auto.. when I changed that I selected Dolby.

restarted Apple TV.. still getting audio to arc, but not amp. :-/
 

Are you playing a 5.1 audio stream?

Perhaps try a movie from Netflix like ‘6 Underground’ or maybe an episode of ‘Jack Ryan’ from Prime Movies. Then see what your audio output is on the ‘Now Playing’ screen for your Arc in the Sonos App.

When I look at the Sonos app when the tv is pushing out audio, it says “stereo pcm” - that could be another clue 

That was it- when I played a movie it switched to Dolby.

Ok then!

Before, I was testing playing YouTubeTV.. is there a setting that would force audio to come from all the speakers when it’s not Dolby? 

Not for stereo TV audio - that usually only plays on the front HT channels only.

There are some settings you can try though…

Goto "Settings/System/yArc Room Name] and look in ‘Surround Audio’.

I will perhaps suggest changing the Ambient setting to ‘Full’ for music audio.  Also you can try adjusting the ‘TV Level slider Bar’ and set the distance of the surrounds to a greater value to get more from your rear speakers during both TV and Music playback.

Don’t forget to perhaps also go back and see if the ‘Auto’ sound out works on Apple TV too, as that will give you LPCM audio which is ‘supposedly’ a slightly better quality, but personally speaking I’m happy with the Dolby Digital surround setting.