Sonos Arc loud pop then audio loss

We did have a user many pages back that was affected and had a TV that used Dolby MAT for output. No Xbox or Apple TV had ever been hooked up. 

Both gunshot pops (rapid fire) and single pops, mixed and unpredictable. At times it sounded like electrical pop sounds and I did jump to the conclusion that something had blown the Arc speaker(s) until the reset and fantastic sound since. 

Even triggered some Pops while unplugging to try a reboot and accidentally touching the volume buttons on top, so even the interface sounds could generate pops instead of the intended sound. 

I didn’t notice the audio codec but it was popping for anything that we threw at it: both Sonos Radio Rock Pantheon music (and any other stations), Amazon Music, and local CBS television which was likely DD5.1 at that time.

I didn’t know about this and similar threads during the bulk of this, so I can’t say for sure that we threw any ATMOS source at it. But definitely no AppleTV, no Xbox and CEC was turned on (controlling volume up & down with TV remote) and spatial or ATMOS (whichever it is) in the S2 app was also turned on. The former two seem to be getting lots of redirection blame for triggering pops but this was direct HDMI eArc connected to a mid-brand TV. The remedy I’ve read is to turn CEC and spatial/ATMOS off but that seems like a terrible remedy given both are KEY benefits of Arc.

Again, all sounded great for a couple of hours in which I couldn’t run Trueplay due to some uncontrollable environmental noise in the area. After that was silenced, I ran it, expecting Trueplay balancing as I had done several times with another Arc and Move speakers... and that process was immediately followed by Pops (singles and rapid fire). After several restarts, it was the same.

Only sleeping on it and then trying factory reset, setting ARC back up again, linking it with the two 300s again, etc (basically everything I had done the night before EXCEPT running Trueplay) brought back excellent Arc sound with both music and television. Been pounding it all day & evening since yesterday with all kinds of sources included confirmed ATMOS stuff from Amazon app on that TV and not a single pop. Everyone is gushing how great it all sounds (as we all expect from Sonos). 

While it’s terrible to jump to any conclusions on only one instance of any cause & effect, my gut feel is that if I ran Trueplay again right now, the Pops would immediately follow and the whole process would have to be redone again to get back to the great sound I have now. While one should never pass judgment in one instance, those same guts say this problem MIGHT be centered in Trueplay, which in the setup process is something people are told to run. In my case, I bailed on the initial setup process at that point due to some noise I couldn’t control (waiting for silence before running Trueplay). And that led to this potential discovery that may prove to be helpful for others. 

Hopefully, a few with the Pops can recall running Trueplay and opt to give this a try. Resetting to factory is easy, as is setting the reset speaker back up again. When it gets to the Trueplay step, bail on the process and try playing something you know was making it pop before (and play something through AppleTVs and/or Xboxes too). If a few people can confirm this possible remedy, Sonos could dig into the Trueplay programming to find what I suspect could be some selective bugs that basically lead to the pop problem for some of us. 

Some programming bugs makes much more sense (to me anyway) than “turn off ATMOS” or “turn off CEC” for THIS speaker… and it seems doubtful that Apple, Microsoft and select TV manufacturers would ever alter their audio playback hardware or software to “fix” this problem for Sonos if it was really them.

I’ve run Trueplay on my own Sonos stuff several times and never had the problem, so perhaps it’s also linked to select combinations of Sonos speakers? In this case, I had already linked an Arc and two 300s in a single room before running Trueplay. Maybe that’s one of the combinations that can trigger this?

Again, perhaps I’m onto nothing here (a good scientist would run cause & effect several times to see if- in this case- running Trueplay again now would bring those pops back without changing anything else (I suspect it would)), but we enjoyed the same CBS channel likely playing Dolby 5.1 for stretches of time before I ran Trueplay. So if Dolby MAT is at fault, it would seem Arc should have been popping before Trueplay ran too. Sounded great… right up until I ran Trueplay.

After that, every audio source made it pop, including Sonos own radio stations, which are presumably NOT Dolby MAT, nor even running through the television at all (wouldn’t Sonos radio just direct play on Arc via ethernet connection to router?). I use an Arc in another room for music only- no TV connected at all- and listen to Sonos radio on it frequently (has been trueplayed several times over the years and never had any pops).

And again, since the reset early yesterday, the otherwise exact same setup, cables, TV, etc has been playing near non-stop- including more of those local TV stations- with not a single pop. So if Dolby MAT is at fault, it seems there would have been lots of pops when running stations playing Dolby Digital. What’s different since yesterday? The ONLY thing: Trueplay has not been applied.

New Arc owner here. With Sony now rolling out the PS5’s Atmos update, should I be cautious of using that mode for audio output?

Based on what I have read on reddit, yes. The PS5 uses Atmos via MAT as well, which appears to be the cause of the problem.

Yes, beta users here reported the pop after switching to Atmos.

Possibly MAT processing sets a bit(s) somewhere outside of its bounds that sometimes causes issues for something else. Once there was a Mars lander crash because one routine got its one/zero origin mixed up,

---

For non programmers: Array (list) elements are reverenced by a number. Some schemes start the element ID’s at zero (#0 is the first element), other schemes start the ID’s at one (#1 is the first element). There are advantages and disadvantages to each scheme and ultimately it does not matter much which scheme is used -- unless the ‘other’ scheme is used somewhere along the line. For example Programmer ‘A’, using one origin, will call for element #1 (the first element), but this will be the second element in Programmer ‘B’ scheme of zero origin.

In this case an invalid reference could sometimes modify a single pixel in a graphic, but other times could result in output volume set at beyond infinity -- resulting in a ‘thump’ and amplifier shutdown. These things can be extremely transient and hard to track down. I’m glad that I’m not working for SONOS, tasked to fix this, and I sympathize with users who are suffering.

Never thought I’d see an explanation of zeroith vs first indexing on an audio site, but there  you go. 😉

UPDATE: FIVE DAYS LATER

...with all variables the same and no pops. The idea that the TV may be pushing Dolby MAT causing pops doesn’t seem to be applying… else we’d still be hearing pops. Working against a retail exchange window, we’ve been pounding these speakers day & night, basically trying to cause the pops again from all audio sources, including ATMOS and there’s been no pops. CEC is ON and working fine. ATMOS/immersive in the app toggle is ON too. The ONLY variable that I suspect drove the pops that has still not been run again: Trueplay.

On that first setup, Trueplay was delayed for a few hours and Arc + Two 300s setup sounded great for those hours. Then Trueplay was run and there was immediate pops, sounding like speakers were blowing/blown, rapid fire and single pops. Reset to factory, set it all up the exact same way again but did NOT run Trueplay. No pops since. 

Anyone with pops: I encourage you to test this hypothesis, especially if you can make the pops happen in a predictable way: some particular source, music, video. Reset the popping speaker to factory, set it up again but when you get to the Trueplay part, bail on the setup process. Then play whatever caused it to make the pop sounds before this reset. 

If this problem is centered in a variety of other manufacturers hardware- AppleTV, Xbox, select TVs, Playstation, etc- how is it ever going to get resolved? Those players are not likely to all adapt their audio output to fix this Sonos issue “affecting a small number of individual users.” 

On the other hand, if it is a software thing- which makes so much more logical sense than blaming many others and/or “turn CEC off” and “turn ATMOS off”- debugging some software has the potential to fix this for up to everyone affected. 

While this guess has great potential to be WRONG as it is based on only a single instance of cause & effect, my guts say there may be a solution in waiting here… unlike getting Sony + Apple + Microsoft + various TV Manufacturers + <who else> to change their audio outputs. Whether complete or only partial, at least it would be something Sonos could potentially remedy by their own actions. 

If anyone is willing to reset to factory, set up again and then see if the pops continue, post your results. This weak guess could be wrong but if it is towards right, it would give Sonos somewhere to focus some attention. These speakers sound so freaking good without the pops. I hope others with this problem find a path to enjoying them too. Maybe this one? Maybe something else?

I’m using a Beam Gen 2 with an Apple TV 4K 2022. I haven’t had pops like people in this thread describe, but have suffered audio dropouts every 5-10 mins when using Netflix with Dolby Atmos enabled. If I select Dolby 5.1 the pops go away, so I suspect this is the same issue.

we watched three episodes of a show last night and there were regular audio dropouts throughout. So I’ve taken your advice and have reset the Sonos and set it up again without Truplay and so far so good. We watched two more episodes and had no dropouts at all.

Obviously early days but seems promising so far. I’ll test for a few more days and report back.

i also encourage others to give this a go and report your findings here.