Sonos Arc loud pop then audio loss

@Corry P THANK YOU for acknowledging the issue. That step alone make me feel a lot better. The runaround from Sonos support (go change the cable) had been disheartening.

@bromos I have the exact same model TV and my Apple TV is hooked up to one of the physical HDMI 2.0 ports (XBOX is on HDMI 2.1, Arc is on the shared HDMI 2.1/eARC port). I’m afraid I get the pops all the same.

However, I believe having the port set to “Standard” takes you all the way down to HDMI 1.4, as in you can’t even get 4K60 or HDR on “Standard”. I recommend checking into that on your Apple TV.

I’m not exactly sure what the limitations are of “Standard” but I ONLY use HDMI3 for the ARC, and from what I’ve read the worst case scenario is that I’m getting compressed Atmos instead of uncompressed when doing so.  The weird thing to me is that I would expect if you enable eARC that it would force HDMI3 to Enhanced, as they SHOULD go hand in hand, but that doesn’t seem to be the case, as I have eARC enabled with HDMI3 set to “Standard”.  I wish they wouldn’t dumb this stuff down so much that we have no idea what’s going on so it could help with troubleshooting some.  Technically speaking, Atmos shouldn’t work at all unless using HDMI2.1/eARC, so maybe eARC enabled “overrides” the Standard/Enhanced setting somehow?  There are some on other forums (AVS) that have this same combo without issues and I wonder if its this setting (leaving it as standard) as the reason why?  I’m really hoping this “fixed” it for me, but I’m sure I’ll be proven wrong at some point in the next day or 2.

I have AppleTV 4K gen2 on HDMI1 set to Enhanced Format running at 4k60 DV and Xbox Series X/PS5 on a 2.1 switch on HDMI4 set to Enhanced as well (for the awesome crappy fake 4K120)

Lol! I feel your pain. Sony conned us good with the 900H. Advertise as 4K120, actually deliver 3840x1080p.

I misunderstood your earlier statement. I thought you had your source device port set to HDMI “standard”. I didn’t realize you were talking about your ARC port.

I have replicated your setup and can confirm that I get the Atmos symbol in the Sonos app after setting the HDMI3/ARC port to “standard” with eARC still set to “Auto” (AKA on). Of course, there’s no telling if it’s compressed from the app. I will report back if I get a bang.

@bromos

It’s Friday night and I figured I would test with an Atmos music playlist. HDMI3/ARC set to “Standard” and eARC “on” streaming from an Apple TV on HDMI2/HDMI2.0. 

I triggered the pop in fewer than ten minutes. :(

Was that whilst using the default uncompressed LPCM codec? If so, then maybe try the ATV audio settings set to compressed DD+ (Atmos) audio-output instead and then try DD5.1 and perhaps try to establish if it’s down to a particular audio codec from the Apple TV. 

If a particular codec can be identified as the culprit, you can at least set it aside and never have to hear the popping sound ever again.

Apple TV decodes all audio to uncompressed multichannel LPCM before sending it on. Technically it’s pretty cool because it means system audio, including Siri, are seamlessly integrated even when listening to Atmos content.

The only option is to change everything to DD5.1 (no DD5.1+). That means no Atmos. And without Atmos, no pop. 

@ProfessorFrag 

I should just add that with Linear PCM switched off, that whilst using DD+ or DD 5.1 codecs, you don’t need to have eARC enabled on the TV either, so you may want to try that both enabled & disabled with those codecs too, just to perhaps see what difference that may make (if any)? 

Our two posts crossed - it makes me think perhaps there is an issue with the LPCM format with Atmos, but obviously that’s just a guess on my part, but it seems to be one of the common denominators whenever people report this popping sound. 

Did some replication testing this morning with the same playlist (Dance in Spatial Audio) on Apple TV/Apple Music. 
 

First attempt, pop in two minutes on the first song. 
Second attempt, 45 minutes of playing with no pop. 
 

So this remains as difficult to replicate as ever. 

This has been my theory for a long time — between Apple TV, Xbox and Roku — it’s the common denominator: Dolby MAT.