The Arc would tell the TV LPCM surround is not supported and then the TV would only output stereo to the Arc I would presume.

If you choose Sonos you’re stuck with the choices Sonos makes. DTS or LPCM surround formats are not supported. To Sonos this must not be a big problem - if it was, they would have fixed it. So the large majority of Sonos users will not own a game computer (LPCM) or a blu ray player (DTS) - so will stream from their native TV apps, for which DD+ and Atmos are more important.

Above it is mentioned the PS4 outputs LPCM - it will also output DD, so the problem is not as big as it is with, say, a Nintendo Switch - I have read this will only do LPCM.

It also depends on the codec conversion of the TV. If the TV can convert LPMC to a codec like DD+ then it can output it to the beam. I don’t think the TVs can pass LPMC via ARC so some sort of conversion would be required. I think the next generation of TVs will probably be more capable of this If not you’ll just get stereo pcm. 

This is disappointing, I pre ordered mine as thought a secondary HDMI to connect the Apple TV was a given. Would an atmos receiver do the trick then ? Apple TV → avr ← ARC 

Since you can only connect the Artc to an HDMI-ARC connection, the receiver would have to have such a connection, that would act as an HDMI-ARC to the Arc. I do not no think this is possible.

If you ar thinking about buying a receiver with this kind of capabilities; I would rather go all out and not bother to go the Sonos route - the Arc is a 3.0 speaker, not a center, so your receiver would act as a (very capable, very expensive) HDMI-switch. If you want Sonos for such a receiver, buy a Sonos Port.

+1 to the other disappointed people here.

I stream primarily via an Apple TV connected to an AVR connected to a television. I was going to buy an Arc and ditch the AVR setup when I bought an eARC TV later this year.

It seems this is not possible, given the LPCM limitations / discussion above. So basically if you are in the Apple ecosystem, and like your Apple TV, as I do, Sonos doesn’t want your soundbar dollars.

I own a lot of Sonos gear, but I find their soundbar product strategy very hard to understand.

Dave Ings

I find your logic odd. It’s Apple that is apparently restricting the Dolby Atmos signal to MAT, not Sonos. Assuming you can hand the appropriate signal to Sonos, it will play it. Sonos has zero control over what systems you TV supports. I’m not sure what Sonos can do, other than to petition Apple to change their stance, and we’ve seen how well that has progressed on the ‘on this device’ front. 

If, and I stress the if, this is a problem with Apple TV, it lies directly on Apple’s shoulders, and the TV sets we’ve purchased. Sonos has said they’ll play Atmos encoded in Dolby Digital Plus over HDMI ARC, and in TrueHD over eARC. How can this be laid at their feet?

I will reserve my judgement on Apple TV until I see how my Vizio passes the signal to Sonos...and if it still doesn’t work for me, I’ll reserve my complaints for Apple’s refusal to use anything other than MAT, and me for purchasing a TV that Doesn’t support eARC, probably in equal measure. But it’s not a Sonos issue, by any stretch. They’re just the receiver of the signal. 

I’ll reserve judgement too. It’s early days - the product isn’t shipping yet! 

But I’ll be on the lookout for guidance from Sonos on how the Arc can be used (or not) with an Apple TV and a modern (2020) TV with eARC. If not, well, being handed a reason to buy a new AVR wouldn’t be the end of the world. :-) 

Dave Ings

Don’t blame Apple. The fact is that it is the receiving device’s job to interpret audio signals, if the receiving device cannot do so then it is just not up to date with common audio signal processing.

The stance you are taking is basically: Sonos says our receiving device does type X audio processing, so every manufacturer of tech equipment in the world must now support products the way we do, thanks. The correct way to handle it is: We understand that there are a large variety of audio signal processing methods, our receiver is prepared to support them.

And no I don’t care if you disagree. The fact is that Sonos and Bose are the only two audio product brands that take the approach of “my way or the highway because everyone else can go F themselves if they dont do things the way we do”

I’m in a similar boat — currently I have a non-ARC projector connected to a Sonos Beam via an HDMI switch that has an S/PDIF optical output. This works well enough, but looks like it would have to change if I upgrade to the Sonos Arc and wanted Atmos audio.

I understand Atmos is not supported with optical, so I’m looking this “HD Audio Extractor” which splits HDMI into HDMI + Audio-Only HDMI: https://smile.amazon.com/OREI-60Hz-Audio-Converter-Extractor/dp/B07T6CDPQJ/ (It claims to support Atmos).

So in theory I could plug my HDMI sources into the input, with HDMI out to the projector and Audio-HDMI to the Arc. Maybe that would work?

Won’t work. The Sonos hdmi is an output not an input and only supports ARC/eARC audio so it will ignore audio on regular hdmi channels.

Sonos isn’t know for budging on these things so I think the best bet is to reach out to the support at hdfury (a third part company known for similar products) and continue to let them know their is an interest in such a product. Enough interest and one may be created.
 

It would also be interesting if someone did a teardown of the optical to hdmi adapter that comes with the beam and arc since it is the only known device that is able to input audio to Sonos device hdmi ports and my give some of the more tech inclined forum members clues as to a solution.

This device does claim to have ARC audio out, but yes, hard to know until the Sonos Arc actually ships and we can test it out for real.

These devices seem to support eARC pass through coming back from the TV and sending it out. They don’t appear to create their own eARC output from an HDMI source input. 

It’s just poor wording for extracting audio from an arc connection that has already been established between a device and an arc television. The specs claim the audio comes on a blanked out 720p video stream.

Hello everybody,

I’m also considering buying the Arc (and also a new TV when there is a nice offer or so). Since my room isn’t that big, my 5.1 Sonos Beam Setup is totally fine. Therefore, the only reason to upgrade is the Atmos support.

Since the Arc only have one HDMI port, the TV has to pass through the audio signal from the media player right (e.g. Apple TV)? As far as I know, there is no TV on the market right now, which is capable of passthrough an LPCM signal. For example, the Sony AG9 (which is Sonys OLED flagship right now) can only passthrough Dolby Atmos via Dolby TrueHD and eARC (https://www.rtings.com/tv/reviews/sony/a9g-oled). So, therefore, it would make no sense if the Sonos Arc would support LPCM since there's no possibility to get an LPCM audio signal to the Arc. I’m not an expert so I might have a fallacy somewhere, please correct me if I’m wrong.

Regarding the Apple TV, I haven’t found a source that confirms that the Apple TV outputs LPCM audio formats. On the official Apple website, it only says “Apple TV 4K uses a high bandwidth form of Dolby Atmos that doesn’t work over ARC connections.” In this discussion, however, thy guy says, that Apple is using the Dolby Metadata-Enhanced Audio Transmission (MAT) format. As far as I understand from this document (page 12), Dolby MAT is PCM audio containing Atmos Metadata and is unpacked from Dolby TrueHD bitstreams. The Xbox is also using Dolby MAT because it is an audio format which is already decoded when it enters the TV and therefore there’s nearly no lag. Again, I’m not an expert and might have somewhere understood something wrong.

But since Sonos Arc supports Dolby MAT, we should be able getting lossless Dolby Atmos using our Apple TV, shouldn't we? (Assuming the TV has an eARC port which is needed for Dolby TrueHD and Dolby MAT)

I agree with your logic. I’m concerned that you’re going to be retired from F1 when it resumes.

There are relatively few TVs on the market that can deal with a TrueHD (and I assume MAT) signal, which is mupildly frustrating. I’m pleased that Sonos has ‘future proofed’ the Arc for new TVs coming, but right now, I’m not sure that my Apple TV is useful for Atmos content, such as there is. I am continuing to look for an external device that will take the HDMI signal and convert it to an eARC signal before the video is passed to the TV. I imagine this will be somewhat more expensive, if it’s made, than the simple HDMI switches that just pull off to an optical output, or still use the electronics in the TV to pass back that ARC or eARC signal. So far, I’ve not found such a device, but seeing as the potential market for such has increased, I have to wonder if it won’t show up soon. 

Good analysis. I’ve been looking too with no luck finding yet. If you find such a solution please post so we can all benefit.

I will indeed, the moment I find such a device. I fear it may not be before I get my Arc, however, as the time to market versus the new pent up demand is a bit short. It’s almost tempting to hire my own engineering firm and make one myself, and then sell it. But I suspect they can do it faster in Asia than I can here in the US, since it might be an extension of devices already designed and manufactured. 

Hey @dcb17, I’ve got the same setup as @AirKilroy (LG C9 with eARC, Apple TV 4K and an ordered Arc)… your insight here was really helpful. To dig a bit deeper, though, when you say ‘you will be fine’, is that with regard to just Netflix apps etc., as I’m mad keen to understand further the concerns around Apple TV playing TrueHD 7.1 content from apps like Infuse out as LPCM… do you reckon the Arc will then not be able to process/downgrade to 5.1 or stereo?

Thanks for your help.

Every user with an eARC TV and an Apple TV 4K should be fine. So no worries @shnuggleberry.

HDMI eARC is able to transmit the “special” format that Apple uses for Atmos. It was widely reported in the past (when the new Apple TV 4K was released) that the Apple TV 4K (only the 4K model is able to play Atmos!) plays Dolby Atmos in a “special” format (DOLBY MAT = “Dolby Metadata-enhanced Audio Transmission”). It looks like the reason for that is, that they want to mix the System Sounds and Siri voice over into the sound mix. By doing that, they have to decode the DD+ w Atmos Singal and put it back together with the System Sounds as a “DOLBY MAT” signal witch is a LPCM signal with Atmos information packed in it. This DOLBY MAT signal cannot be transmitted over regular HMDI ARC but only over eARC.

When “reviewers” with older TVs are reporting, that they managed to get Atmos from Apple TV over a regular ARC (not eARC) connection out of their TV, the reason is probably their TV. Some TVs are apparently able to convert an DOLBY MAT w/Atmos signal into DD+ w/Atmos and send it via regular ARC to a soundbar. It looks like older LG TV (7,8 series) are able to do that with a regular ARC connection if they are updated to the latest firmware (support for that came later with a firmware update).

Will this also work for my LG E6 ?

There is an option in the settings to output Dolby Digital Plus.

Who knows, this TV doesn’t do eARC, so we have to wait for someone to actually try it, or for Sonos to tell us which TVs are compatible with Apple TV + Atmos over ARC. They must have some idea as one assumes they have tested it with a bunch of different devices.

Thanks for the support, @GenAckbar73. Again, I could very easily be wrong… but from what I’ve been reading, the ‘special format’ you mentioned will work just fine only when I’m streaming in Apple TV apps like Netflix, Apple TV+ etc., however… other 3rd party app are forceded to output audio as LPCM from Apple TV 4K, meaning it would be downsampled for Sonos Arc? Not because of eARC, but because of the codecs supported by Sonos Arc, if that makes sense?

Grrr, all so confusing! I use a beautiful app called Infuse to stream my Blu-Ray rips (incomparible, ease of use/presentaiton-wise to Plex and Plex-like apps, in my opinion), with Apple TV 4K and an LG C9 (I’m very, very lucky here, I know… so odd to be moaning) and soon a Sonos Arc - so with all such modern equipment it would be crazy if Atmos just didn’t work!

It may be overkill but I’m considering purchasing a relatively affordable  LG SM90 (SM9000) tv which has EARC to act as a ‘receiver’ between the Sonos ARC and my projector.

i would also need a HDMI splitter to feed both the TV and projector from an Apple TV / Blu-ray player.

The TV could sit behind the projector screen and could be used for occasional viewing when the screen is up. I also believe LG TVs have a ‘screen off’ setting.

In this way I could have lossy Atmos from the connected Apple TV and lossless Atmos from a connected Blu-ray player.

If and when a company develops a HDMI matrix with arc capabilities it would probably cost a few 100 anyway.
Why wait for this technology which would be fairly niche and may never happen.For a few 100 more you could have the solution now with the added benefit of a second screen.

Any thoughts ?

I’m considering the same thing but with a smaller Samsung 43" Class TU8000.

Anyway, what splitter have you found to support everything?

Trying to get an answer to this question via this discussion:  will I get Atmos to my Arc if I feed the Arc directly from Apple TV, bypassing my TV audio, where the ATV app supports Atmos?   I believe the answer is no, as a result of the limitations of the type of ATV output - is that correct?