Try unplugging the two One SLs from power for a couple of minutes and reboot your router. You can also try separating the Ones SLs as a stereo pair and switching the position of the speakers where the left speaker is now the right speaker and the right speaker is now the left. Then pair them as a stereo pair and test again.
Hi GuitarSuperstar-
Thanks for the advice. Yes, I did actually do both these things during my troubleshooting. They work temporarily but they don’t fix the problem. I.e., I can indeed get the paired speaker set working again (in a number of different ways, the easiest being removing and re-adding the pairing through the Sonos app) but the issue always just occurs again when I re-start an Airplay session.
Luckily, since I can always get the pair working again, I do have a “workaround” for the meantime - it just means I can’t use AirPlay which stinks because it’s a really nice feature! ;-p
I’m curious to know what Sonos support said when you called them, after you recreated this situation, and sent them a diagnostic from your system.
Hi Airgetlam-
I plan to call Support tomorrow and walk through this situation, I will reply with anything I learn.
Longer answer: I was on the phone with support today, but unfortunately we didn’t uncover the real problem - it appeared as though my problem was addressed since as part of the troubleshooting process they walked me through re-setting the speakers and that did provide a temporary fix. It was only later when it occurred again, and through playing on my own was I able to discover the real cause. Of course by then it was after closing time on the east coast.
Interestingly, while my initial search didn’t find anything, I’ve since found at least one other person reporting the same issue:
You replied to that person as well and I have a question about something you said. You asked if they were letting Sonos handle the stereo of if they were sending two signals (and one might be getting interference). Interesting theory. I was unaware I had the option, however - and how would I know which I’m doing? As far as I can tell, I can just “use AirPlay” or “not use AirPlay”. I would *assume* that AirPlay is just sending one data stream for all the music to Sonos and that Sonos is handling the L & R, but I really don’t know...
This type of stuff intrigues me so I setup a test of my own.
Network setup:
- Tri-level home
- Mesh network with 3 Asus routers using Ethernet backhaul
- Main Node: Level 1 (lowest level)
- 2nd Node: Level 2
- 3rd Node: Level 3
- 1.2GB incoming via Xfinity ISP
- Wi-Fi Download 313 Mbps *
- Wi-Fi Upload 41.5 Mbps *
- Wi-Fi Ping 11ms *
- Wi-Fi Jitter 3.3ms *
- Wi-Fi Packet Loss -% *
Sonos:
- Wired Mode via Boost
- Sonos S2 v14.0.2
Device
- iPhone 12 Pro Max
- iOS 15.3.1
Wanting to stress Airplay2 as mush as possible I grouped three (3) stereo pairs of speakers. I positioned myself on Level 2 to run the test. Played a 5 minute song 3 times in a row via AppleMusic with no drops on any of the stereo pairs.
Test Speakers
- Level 1: Five x 2 with Sub
- Level 2: Sonos Amp with wired floor speaker x 2 with Sonos Sub
- Level 3: Sonos One x 2
Conclusion
@Mike O definitely has an issue somewhere. However, judging from my testing the issue may not be with Sonos as a “bug”.
I’d look at network setup, device iOS & Sonos app versions and make sure they’re up-to-date. Also check router firmware for an update and that Airtime fairness is turned off. If extenders or access points are involved make sure only the main node has DHCP capability.
I'm no expert but my Sonos testing thus far didn't reveal any AirPlay2 issues of the nature described. That’s not to say it won’t occur later
@Mike O please keep us posted.
* These results will vary based upon the location of the server. The numbers presented are an average of three (3) speed tests.
Edit: Maybe it’s something isolated to the One SL; given the post mentioned by @Mike O . But that is a stretch since the One SL is supposedly a One without voice assistant capability
The question really is ‘are you sending more than one AirPlay 2 stream to Sonos’.
There is, in my estimation, limited bandwidth between your Apple device and the Sonos system, especially for an iPhone or iPad. It makes much more sense to send a single stream from the Apple device to the Sonos, then use all the software and bandwidth available to the Sonos to group any speakers and send the single incoming stream to all ‘grouped’ rooms. It really is what Sonos’ system is designed to do. There’s really no reason to strain the resources on the Apple device to send X number of AirPlay 2 streams to X number of speakers.
For some reason, people tend to forget that there’s no need to send a separate stream to each ‘room’ from AirPlay 2. Send one stream, then let Sonos distribute it as necessary.
By the way, I wouldn’t think that has anything whatsoever to do with your situation. But with so few instances or explanations for the community to work with, it does seem to be something that could be uncovered by the hard data in the diagnostic, something we forum denizens have no access to, sadly.
The question really is ‘are you sending more than one AirPlay 2 stream to Sonos’.
There is, in my estimation, limited bandwidth between your Apple device and the Sonos system, especially for an iPhone or iPad. It makes much more sense to send a single stream from the Apple device to the Sonos, then use all the software and bandwidth available to the Sonos to group any speakers and send the single incoming stream to all ‘grouped’ rooms. It really is what Sonos’ system is designed to do. There’s really no reason to strain the resources on the Apple device to send X number of AirPlay 2 streams to X number of speakers.
For some reason, people tend to forget that there’s no need to send a separate stream to each ‘room’ from AirPlay 2. Send one stream, then let Sonos distribute it as necessary.
Judging from @Mike O post he is only sending a single AirPlay2 stream to a Stereo pair. Unless I missed something there are no other rooms involved. However, I do agree to start AirPlay2 to a single speaker or stereo pair then group in other rooms.
Agreed, but the question asked was about my post on another thread. Different situation to the OPs, I think. My response was to ‘I have a question about something you said’.
Deleted. 
I’m having the exact same issue described at the top of this chain. Same room stereo pair works with Sonos app but when AirPlay is used it breaks the pair and only plays from the left speaker.
I’ll repeat my question from earlier in the thread:
“I’m curious to know what Sonos support said when you called them, after you recreated this situation, and sent them a diagnostic from your system. “
There’s just not enough information in your post to hazard a guess.
Full disclosure: I’m not a regular AirPlay user, but I have tested it a few times. As a new test I started playing the default U2 album on my iPad, enabled AirPlay on the iPad, and sent the stream to a pair of MOVE’s. Both MOVE’s played and remained paired after I stopped the AirPlay stream and started a new stream with the SONOS controller.
Same results with a pair of ROAM’s (one ROAM and one ROAM SL). I don’t have a pair of ONE’s powered at the moment, but I expect the same results.
My thought is that there is a wireless issue of some sort. Wireless issues leave tracks in the diagnostics.
