That depends on your A/V receiver, and if it has the capability to create, not just pass through, an eARC signal.

I’d have to give this some thought, but at first glance I don’t think it would work. 

Even if your receiver had ARC/eARC, the receiver is going to expect to be the final destination for the audio. E.g., the receiver would be accepting the audio signals from the television (whether through a broadcast channel or a built-in app) in order for the receiver itself to  do the processing and output to its own amplifiers. I can’t think of a scenario where a receiver would go ahead and “pass through” the audio signal to another device (basically like a pre-amp would for analog signals). 

I’d love to hear more about this from people who are more knowledgeable about this than I am, though. 

I have a similar situation with a 2014 Sharp Aquos TV. To old to pass thru Dolby Atmos to my Arc.

I it an older smart TV but i do not use its internal apps i stream to it from Amazon Fire device. My question is with a proper recevier that has HDMI ARC or ARC+ out can i not go to the receiver with my Fire or Apple TV device and out to the TV with video and out to the Arc with audio? meaning the Audio is not passing thru the TV.

No, this won’t work. The receiver has HDMI-ARC in order to be able to get the audio from the TV’s built-in apps and tuners and then to amplify it and send it to the speakers connected to the receiver. And the Sonos Arc doesn’t have a traditional HDMI input which would accept an output from a receiver (quite weirdly it actually has an HDMI OUTPUT to be able to receive the audio return channel from the TV - hard to wrap the head around). 

The only solution we currently know of that will enable an external HDMI to send full range audio like Dolby TrueHD / Atmos from any device to the Sonos Arc is an upcoming adapter from HDFury called Arcana: 

https://www.hdfury.com/product/4k-arcana-18gbps/

They’re accepting pre-orders now and it will do exactly what you want - allow you to hook up your Amazon Fire or TV to the Arc to get Atmos while still keeping your old TV. 

(@BobbyB86 - this is the answer to your original question, too.)

Thank you BobbyB86, I knew I would have challenges with my older TV and fully utilizing the Arc but i do have to say it as standard surround play bar sounds a bit better than the original play bar that I have relocated.

You have helped me clarify what is available to work with and the link to arcana is great, i will consider this too.

regards

I need to give Highfalutintodd the credit for the response, not me. But I need to give you the credit as well for asking the question I had meant to ask. I don’t plan to use my TV apps. I plan to connect a Blu-ray player and Apple TV to a receiver that would then connect to the Sonos Arc and to the TV hoping that I could receive Dolby atmos that way and legit 4K video to the TV from a dedicated Blu-ray player.  I also will look into hdfury, but I find it a little odd that the receiver can’t essentially play the role of this splitter/adapter.

Thank you highfalutintodd for spending time to answer this question! 

ha, good catch BobbyB86 and thank you Highfalutintodd for your response.

@Highfalutintodd This answers the question I was also about to post on Dolby True HD, just pre ordered the HDFury Arcana. Thanks.

If HDFURY arcana works it will be great for Sonos the send their Arc customers a similar product to over come their flagship soundbar the short comings.... Or even strike a deal with the HDFury guys and get a good discount

Has anybody received their HDFury Arcana? Does it work as advertised?

Yes, I have the Arcana and it works great with my 2013 Panasonic Plasma that only has HDMI ARC. Without the Arcana, my TV could only pass through Stereo 2.0 audio from external media devices. With the Arcana, I can now enjoy Dolby TrueHD/Atmos, multichannel PCM, and Dolby Digital Plus/Atmos from my Blu-ray player and Roku Ultra.

The Sonos Arc Experience...

I been a sonos customer for 3 years now, started with sonos one, got the second for the pair and evolved into a sonos home, got the beam when it came out, added a pair of sonos one 2nd gen. as rears and a $600 sub soon after that. My home theather got from nothing to a full 5.1 dolby digital! paired with a samsung 65KS8000, Apple tv 4k, Xbox 1X & Philips hue sync box for the lights! 
after some time the Sonos arc came along and my selling point (to my wife) was the fact the this new addition will be an upgrde to the best surround sound codec out there, Dolby Atmos
and here is when the nightmare started.

First, and after the initial set up, dolby atmos sound showed as “dolby digital’’ or plain PCM.
Got in touch with sonos support thru the app, they were able to connect to my home system and confirmed that my sonos arc wasn’t geting the atmos sound, and after going back and forth, you know going thru the settings on my tv, thru the tv apps, disney, netflix etc. they asked me to set the tv audio to dolby digital+ manually, even when I told them like 20 times that my tv in partucular ONLY HAS PCM OR DIGITAL, NO DIGITAL PLUS OR ANYTHING ELSE.  the way the got rid of me was saying that I HAVE TO CHECK WITH MY TV MANUFACTURE in order to “find that setting” setting that doesn’t exist in my tv, then I basically tell them that per sonos website, dolby atmos should be available with regular arc & dolby digital, (just to be clear, dolby digital & arc, as minimun requirement). so when I confronted them with their own articule, they said that that articule was wrong, 
Piece of advise to Sonos people:
Advertise that besides a sonos arc, you will need a new tv, one that supports e-arc. 
oh! and also revise your articules about compability so people interested in your products won’t waste time.
Listen to Dolby Atmos on Sonos Arc | Sonos

After posting this, will be repacking and returning the sonos arc and consider others options,  like lg or vizio. you know, people that has true knoledge about home theater bussines, not just audio home systems.

@Jpsound2021 I understand your frustration, but this information is included in the FAQ on the Sonos Arc product page:
 

Do I need a TV that supports HDMI eARC?

Sonos Arc can connect to TVs with eARC, ARC, or optical outputs. For greatest compatibility, eARC is recommended.

If you connect to a TV with eARC, the Dolby audio formats supported include Dolby Atmos, TrueHD, MAT, Dolby Digital Plus, and Dolby Digital.

If you connect to a TV using ARC, the Dolby audio formats supported are dependent on your TV model and manufacturer. The TV may be capable of sending Dolby Atmos, Dolby Digital Plus, and Dolby Digital. An ARC connection cannot support TrueHD or MAT.

If you connect to a TV using the optical adapter, the Dolby audio formats supported are dependent on your TV model and manufacturer. The TV may be capable of sending Dolby Digital. An optical connection cannot support Dolby Atmos, TrueHD, MAT, or Dolby Digital Plus.

@GuitarSuperstar THANKS for your response. If I read this before, I shouldn’t had the tasteless experience and all the time wasted for nothing.
P.S. Yes, all this connectivity was done thru HDMI ARC on my tv.
and this tv ONLY supports  Digital, to be clear they should straight up warned people that if your tv doesn’t support digital+ there is no reason to upgrade to sonos arc. noboby will pay $800+ for a bigger sound bar (compared to beam)

Even the picture you provide yourseld says for that Dolby Atmos, DD+ is needed. I understand that it is hard to find out if your TV is capable of outputting this, but Sonos seems up front about it.