I've now been able to test this same scenario with a wired connection to a 2nd WiiM Ultra while grouping and I'm seeing the same behavior: After a number of songs, ~5 songs give or take, the WiiM Ultra begins to lag and get out of sync. Here are the details of my current wired test where I'm seeing the same result:
* Primary Roon endpoint is a Cambridge Audio 851N connected via ethernet. Output is analog XLR out to a Cambridge Audio CXA81. Muse is configured on this device with headroom management (-5) and Parametric EQ enabled.
* The other device in the group is a WiiM Ultra connected via ethernet. Output on this one is USB DAC. In the wireless test with the other WiiM Ultra where I was seeing the same result, the output is optical. Muse is configured on this device with headroom management (-3) and nothing else. On the wifi test no headroom is set.
I'd previously shared log output from Roon in the wifi test showing that Roon is reporting a sync as "OK", and I'm seeing the same from Roon in this test with the wired WiiM Ultra (I'll post the logs below).
I typically have volume leveling set to auto for all my endpoints, and set it manually every time I group endpoints together, but for this wired test I have it disabled just to test if that's an issue (turns out it doesn't make a difference).
I'm assuming this is a Roon Ready/RaaT issue, but is this an issue with Roon Server or with the WiiM's implementation of Roon Ready/RaaT?
Describe your network setup
Wired ethernet (cat5) from each device to a generic T-Link unmanaged ethernet switch. Primary network control is handled by an Asus mesh. Each device is configured for DHCP with no QoS set in this wired test. In the wireless test I did have QoS set for the WiiM to prioritize streaming media but no different, that device still drifted out of sync.
Here is a sample of the logs (filtering only on sync entries) while the two devices are out of sync.
08/03 11:51:02 Trace: [Music-Room-851N + WiiM Music Room] [zoneplayer/raat] sync Cambridge Audio 851N: realtime=6372306455958 rtt=500us offset=1126616455us delta=416us drift=17634us in 182.5385s (96.606ppm, 347.783ms/hr)
08/03 11:51:02 Trace: [Music-Room-851N + WiiM Music Room] [zoneplayer/raat] sync Linkplay Technology Inc. WiiM Ultra: realtime=2792062287958 rtt=500us offset=-2453628712us delta=51us drift=-41701us in 182.5375s (-228.453ppm, -822.431ms/hr)
08/03 11:51:02 Trace: [Music-Room-851N + WiiM Music Room] [zoneplayer/raat] sync Linkplay Technology Inc. WiiM Ultra -> Cambridge Audio 851N result: Success
08/03 11:51:04 Trace: [Music-Room-851N + WiiM Music Room] [zoneplayer/raat] sync Linkplay Technology Inc. WiiM Ultra -> Cambridge Audio 851N result: Success
08/03 11:51:06 Trace: [Music-Room-851N + WiiM Music Room] [zoneplayer/raat] sync Linkplay Technology Inc. WiiM Ultra -> Cambridge Audio 851N result: Success
A few more updates:
Pausing playback in Roon and then restarting it does reset the sync issues for a few tracks, but then the latency/out of sync issue creeps back. When you click pause you can hear the 851N stopping before the WiiM by about .5 seconds. But when I do pause and resume mid-track, when the track gets to the end it will just hang forever with nothing in the logs, no errors, just stuck at -00:00 or -00:01. I have to click >> in Roon to move to the next track, otherwise it will just hang on the end of that track forever. This only happens when I pause mid-track and resume with the WiiM in the group. It doesn’t happen with other grouped endpoints and doesn’t get stuck during normal playback between tracks when the WiiM is in the group.
I found this thread from October on the WiiM forum which sounds like the same issue I’m having. I’ve verified in the WiiM app that both of my WiiM devices (wired and wireless) are set to Sync Audio → Auto Sync.
All devices are running the latest builds/firmware, and no other endpoints (primarily Pi/Ropieee devices) have sync issues wired or wireless; this issue is just when grouping either WiiM with another non-WiiM device.
Based on similar reports from other users and additional community feedback, it appears that the sync drift you’re experiencing with the WiiM Ultra is related to hardware latency not being accounted for by Roon’s RAAT protocol. While RAAT handles network latency very well, it is unaware of internal processing delays caused by specific output paths (e.g., USB DAC, Optical, RCA) or features enabled in the WiiM device, such as fade-in/out or DSP.
A known workaround from WiiM forums is to manually configure the sync delay in the WiiM Home app. This delay compensates for the internal processing time of each WiiM endpoint. Auto-sync features don’t currently work reliably for RAAT streams, so manual adjustment is the most effective approach.
Here’s the process that has worked for other users:
Disable any DSP features in the WiiM that aren’t needed (fade in/out, room correction, etc.).
In Roon, group the endpoints you want to sync.
Play a track with clear transients (e.g., beats or claps).
In the WiiM Home app, go to each device's Sync/Delay settings and manually adjust the delay (typically by increasing delay on the faster devices).
Once dialed in, save the delay values somewhere as updates may reset them.
If sync drifts again during playback, pausing and resuming playback in Roon often realigns everything.
Also, one user pointed out that using hardware-based matrixed multi-room audio systems (e.g., a multi-channel amp with matrix switching) often yields more reliable sync performance than software-based grouping, especially for long listening sessions or complex setups.
Let us know if you’d like assistance walking through the manual sync adjustment steps or need help identifying which output mode on the WiiM introduces the most delay.
Thanks @benjamin and @vadim. Very helpful information. I haven’t had a chance to re-test yet and starting to play with WiiM manual sync but I should be able to get to it soon and will report back. I also found similar feedback from the original post I referenced above on the WiiM forums suggesting the same.
Will keep this thread posted. Thanks for checking in!
After manually setting the sync delay on both WiiM devices (wired and wireless), no luck. Initially changing the delay works really well as expected. But after playing for a while the WiiM start to drift. So it’s not that they’re out of sync based on a delay; it’s that they get out of sync very gradually. I’ve tested with Roon Radio, playing single albums, local playlists, etc, and the drift is always there. The time it takes to start drifting seems to differ, though. Playing a single album will start to drift after about 30 mins give or take; playing a local playlist where it contains tracks of different formats and bitrates, it creeps in a bit more quickly, around 10-15 mins.
Pausing and starting does force the WiiM back into sync, but then it happens again. I’m x-posting this in the WiiM forums as well because I imagine it’s a WiiM issue. For now, I’ve replaced the wireless WiiM with the original Ropieee which never drifts.
Happy to test anything else that anyone might suggest…
We’re glad you have found a workaround for yourself!
Regarding the WiiM sync: We have raised this matter internally with our partners team and will see the results of our internal investigation on this matter.
In case if anything will be found we will contact WiiM from our side to resolve the issue.
Thank you for collaborating with Roon in this question!
