ATV 4K has been updated and now everything plays in Atmos.

Have you read the tooltip?

’Apple TV uses a Dolby MAT connection for glitch-free playback across formats. Older receivers may indicate an Atmos connection, but original mixes will not be modified.’

With the new Continuous Audio Connection, using Dolby MAT on everything, Sonos will register everything as Atmos, it’s not playing Atmos on everything though, only on Atmos content. 5.1 will play as 5.1, it just has a Atmos badge at this moment. 

I’m sure there will be an update where Sonos can differentiate the Dolby MAT having Atmos metadata or not.

And for now, Sonos still doesn’t support/chase beta releases, I suspect to many hours chasing things that may or may not actually release. If Sonos were to make any changes, I’d expect it to be after Apple releases 26.4 as a final release, and not before. 

I have to say it…

I’m glad Sonos makes its beta testers sign NDA’s. IMO it’s articles like the one sited by the OP and then posted in a community like this that do more harm than good.

I’m an Apple “fanboy” even in my advanced years. Some might say I live and breathe Apple; and also Sonos 😂. However, that’s my business...each to their own.

However, I hate that Apple software beta’s; unlike Sonos, always seem to make it into the wild before it’s time (admittedly with the exception of the Sonos App debacle in 2024). Frankly, this ATV update regarding Dolby Atmos and popping issues in soundbars apparently has nothing to do with Sonos and never has.

That said….is enough.

In the past Apple has had a habit of making late changes just before releasing an update. 3rd parties working with the beta’s got blindsided by the formal release. Of course the in-house Apple applications were updated and worked. This causes Apple users accuse the 3rd parties as being incompetent and vow to avoid 3rd party applications.

I am not an Apple “fanboy”, but I have an iPad that I must use for work applications.

From what I’ve seen, when there is any issues between integrations with Apple/Googe/Amazon and smaller company’s hardware or software, the default assumption is that the smaller company is to blame.  It doesn’t really matter what sort of communication and timing occurred.

If only Sonos had followed that philosophy when they released the new app…

So now after TVOS 26.4 was released, I hope Sonos will start to analyse the situation and try to adjust their audio format recognition. Imo there has to be some kind of steady check for format changes during the continuous mat stream. 
At the moment I prefer to deactivate the option, because everything is shown as Atmos. 

I’m not sure this a Sonos issue. In the AppleTV settings app if Dolby Atmos is turned off the Sonos App shows the audio stream codec correctly.  Therefore, IMO the ATV app is sending false audio information to Sonos when Dolby Atmos is on. Meaning Dolby Atmos identification within the ATV is hi-jacking the audio identification for lessor codecs (if that makes sense 🤔).

But what do I know….🤔🤔🤔

After further investigation I found that turning off “Continuous Audio Connection” (CAC) in ATV resolves the issue of every thing showing as Dolby Atmos. So my suggestion is to leave CAC turned off; unless there is need for it.

Yes, that (to turn off CAC) is my final decision at the moment and keeps the status like it was before. 

I‘m also not sure, if it depends on Sonos or Apple to fix the „always Atmos shown“ issue. I was guessing Sonos, because Apple says that the issue could appear on older AV receivers and not in general. 
I suppose that Sonos misinterprets the mat signal as „definitely Atmos“. If Atmos support is turned off on ATV Sonos gets no mat signal that could be misinterpreted. Maybe if Sonos gets mat there has to be a double check if it’s Atmos inside mat or another format. 
But also maybe you are right and Apple has to add the exact format information within the mat signal. 
ATV User experiences with other non Sonos Atmos receivers would be interesting to see how it works there.

Another reason I think it’s an Apple Issue is the highlighted portion of the statement in the article

• It appears that Apple added this new setting, in part, to address complaints from Apple TV users who use Sonos speakers paired with AV receivers. Some users have indicated they hear popping noises or awkwardly low volume levels on certain channels, specifically with 5.1-channel content

What Sonos speakers “Paired” with AV receivers? How is that done? Must be some non-standard  Sonos integration with an AV receiver. The only way to bring an AV receiver into Sonos is via a Connect or Port...and that’’s NOT pairing 😂

Soundbars are also considered “AV Receivers”. Anyhow, Arc + Arc Ultra are anything but old.

• Continuous Audio: Select to turn Dolby MAT on or off. Apple TV 4K uses a continuous Dolby MAT connection for seamless transitions across audio formats without glitches or dropped signals.

When Continuous Audio Connection is on, older receivers might indicate an Atmos signal, but the original audio plays as intended, which may also affect the ability of a receiver to distinguish a stereo signal for upmixing if the receiver supports that.

 

Play audio in Dolby Atmos or surround sound on your Apple TV 4K - Apple Support

Based on that report, unless I was having an issue (which I’m not, on either Arc / TVs powered by Apple TVs), I’d leave that setting off. The only time I’d use it is if there was an issue. It is certainly off on my systems. 

I have to respectfully disagree with that statement. A soundbar isn’t an AV Receiver. Here’s a WiKi on both...

An audio/video receiver (AVR) or a stereo receiver is a consumer electronics component used in a home theater, home audio, or hi-fi system. Its purpose is to receive audio and video signals from a number of sources, and to process them and provide power amplifiers to drive loudspeakers, and/or route the video to displays such as a television, monitor or video projector. Inputs may come from a TV, FM, or AM tuner, satellite receiver, DVD players, Blu-ray Disc players, VCRs or video game consoles, among others. The AVR source selection and settings such as volume, are typically set by a remote controller.[1]

A soundbar, sound bar or media bar is a type of loudspeaker that projects audio from a wide enclosure. It is much wider than it is tall, partly for acoustic reasons, and partly so it can be mounted above or below a display device (e.g. above a computer monitor or under a home theater or television screen). In a soundbar, multiple speakers are placed in a single cabinet, which helps to create stereo sound and surround sound effect. A separate subwoofer is typically included with, or may be used to supplement, a soundbar.[1]

​@AjTrek1, Technically you are correct. However, I haven’t yet come across a TV manual that distinguishes between an AV receiver and a soundbar.

I suspect they’re ‘lazy’, and mean ‘any device that can accept and translate home theater signals’. In their world, that’s predominately A/V receivers, in our world, it’s both types of devices. 

Their world or mine. I’m not about to start referring to a soundbar as an AV Receiver. Especially not when it comes to Sonos. IMO there’s already too much crossover of terminology within Sonos. If Sonos starts referring to their soundbars as AV Receivers they’re unequivocally losing their minds.

Never tempt Sonos marketing types!

​@AjTrek1 

To be honest I think the 9to5MAC article is an example of bad facts research. It refers to some Reddit posts and the part you highlighted above imo really makes no sense. 
So at the moment I prefer to read what Apple officially says about the feature, what ATV users tell about their own serious investigations and at least what Sonos will tell us after they did their work/ analyses. 😉

Referring to Apples support article I think they are talking about „receivers“ and mean everything (av receivers, soundbars etc) an ATV can be connected to. So speaking of „older receivers“ imho could also include Sonos HC devices. The „older“ in this case may point to the Sonos software that might not be able to detect the correct format within mat signal if Atmos is turned on. 
I know… all suspicion, but just my 2 cents…

​@Schlumpf 

I hear you. However, IMO it’s just bad research on both sides. When lines are blurred between an AV Receiver and a Soundbar it only make for more mis-understanding by folks. I guess my having dealt with AV receivers long before Soundbars (especially Sonos) were a thing I’m a bit anal on the subject. When I say long before I mean when Heath Kits were popular (maybe that’s before your time as well 😂)

​@AjTrek1 

Thx for compliments… 😉 But in the 80s I was a teenager (from 1972) and hifi became an interesting topic for me. But Heathkit definitely was out of my financial range and also not such popular in Germany I think. 
But I totally agree that soundbars and other hardware shouldn’t be called the same as classic av receivers. 👍🏻

The term ‘[AV] Receiver’ is used here as a general term covering all types of home theater systems. User manuals and support articles are aimed at non-technical users and are therefore deliberately kept simple.

As many things in life imo that depends on the personal point of view and demand for technical accuracy. But yes, often such things are kept simple and not differentiated. That might have pros and cons…

Anyway… I just was talking with ​@AjTrek1 about some technical details as a side fact of the topic. So excuse if too much off topic. 😘

Just to drag this out a bit further 😂….

The “V” in AV receiver stands for Video. A soundbar has nothing to do with Video. I’v never heard of an “AV Soundbar”. In fact since a soundbar only deals with Audio there’s no such nomenclature coined with the letter “A” preceeding Soundbar. Audio only is a given.

As a bit of trivia...the AV Receiver wasn’t introduced until around 1985; the soundbar not until 1998. Plus or minus a year for both.

Not that it matters but I was in my 30’s in 1985 well before “Video Switching” was integrated into a Receiver. In fact the early “Video Switching” aspect was RCA Composite (yellow, red, and white plugs), and the forerunner to HDMI was  Component Video (red/green/blue, + audio).

Most probably have no hands-on experience with such (Component video) or very limited at best. In fact anyone born in 1985 is only 41 years old. Component Video was being replaced by HDMI in 2002 which meant they were only 17 years old (high school).

I get it that most people aren’t my age and only know HDMI and/or AV Receivers. However, having a history does have its advantages to fully appreciate what exists today; and not just in audio/video. It amuses me that people complain about putting dishes in a dishwasher. There was a time when they didn’t exist and at one point they were only afforded by the very rich.

So, no I'm not going to acquiese and say it’s OK to blur the lines and refer to a Soundbar as an AV Receiver or anything referenced as such. There is an AV Receiver and then there’s a Soundbar.

That said...if some 20-50 year self-ordained audio/video expert reviewer doesn’t know the difference...I’m here to correct them. 😂

I might turn this continuous audio setting off, not tested enough yet but it seems like all non atmos content is a bit too loud, even at relatively low volume on the arc ultra.