System Output issue using WASAPI devices on RME UCX II (ref#SUH6M8)

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1

What best describes your playback issue?

· Music doesn't start when I press "Play"

What type of Zone is affected by this problem?

· *Directly-connected Zones* are affected.

Does the issue affect all file formats?

· The issue affects *multiple/all* file formats.

Does the issue happen with local library music, streaming service music, or both?

· *Both streaming and local* *library* music are affected.

Do you encounter any playback errors with the "System Output" Zone?

· The System Output has the same problem as my other Zone.

Do you have a complex network setup?

· Both the device and RoonServer are connecting to a *single router*

Please try rebooting your router.

· No, I'm still having trouble

What are the make and model of the affected audio device(s) and the connection type?

· RME Fireface UCX II firmware version 34, driver version 1.251 over USB

Describe the issue

Roon refuses to play through the System Output device or WASAPI devices. I have an RME UCX II running at 48khz with a 256 sample buffer size with Analog 1/2 as the default output in the Windows sound settings. It will happily playback audio when I use the RME ASIO device if I ensure that no other programs are blocking the changing of the sample rate or buffer size, but I like to use Roon for background music and would like to let all other programs take priority over it for these device settings, so this isn't really an option for me. Oddly, the System Output playback works when I set the default Windows sound output to another device. I'm running Windows 11 Home 23H2 build 22631.3958, my RME driver is v1.251 and the UCX II firmware is version 34.

Here's what the Roon logs shows from the moment I click the play button to the moment it displays an error:
08/07 17:08:10 Info: [ui] [popups] Play button clicked: play_pause()
08/07 17:08:10 Trace: waveformshader(473) texture loaded: 31
08/07 17:08:11 Trace: waveformshader(473) texture loaded: 9
08/07 17:08:11 Info: [stats] 2102780mb Virtual, 338mb Physical, 93mb Managed, 1165 Handles, 50 Threads
08/07 17:08:11 Trace: waveformshader(473) texture loaded: 31
08/07 17:08:12 Trace: waveformshader(473) texture loaded: 9
08/07 17:08:12 Info: Alert: Transport: stopping_too_many_failures
08/07 17:08:12 Warn: AddTopLevel: win_alert(2924)

Describe your network setup

My Roon server and client are both running on localhost, so this shouldn't be a problem.

2

Hi @Abel_Aebker,
Thanks for letting us know about this issue. In your logs we’re seeing a lot of this trace from system output.

Trace: [System Output] [raatclient] GOT [24] {"message":"RAAT__OUTPUT_PLUGIN_STATUS_FORMAT_NOT_SUPPORTED","status":"UnexpectedError"}

This is likely a bit of a red herring since you say multiple formats are affected by this. But this can sometimes be an odd result of firewall blockage from windows machines as well - if you temporarily disable it, does the same issue occur?

Lastly, lets refresh your RAATServer database and see if things still persist:

You can generate a new RAATServer instance on your device by following these instructions, but please be aware that this will reset your Roon Settings → Audio Tab to factory settings and I would advise making a backup of any custom DSP settings you have:

  • Create a Backup of your current Roon database
  • Exit out of Roon
  • Navigate to your Roon’s Database Location
  • Find the folder that says “RAATServer”
  • Rename the “RAATServer” folder to “RAATServer_old”
  • Restart the Roon App to generate a new RAATServer folder
3

Hi @daniel ! Unfortunately it doesn’t seem like either disabling my firewall or generating a new RAATServer instance fixed the problem. In both cases I’m getting the same error as before on System Output.

After some further testing, it seems like the issue might be on the Windows or RME side. I tried running MPV with WASAPI exclusive mode and it played back but with a buzzing noise in the background (at some point I had managed to recreate this with one of the WASAPI devices in Roon). When running MPV with WASAPI shared mode, it immediately crashed the program upon any playback. For some unknown reason I can’t consistently recreate these behaviors in Roon.

4

Does the Roon System Output work with the audio device via WASAPI or WDM? In the Device Settings for System Output there’s no option to use exclusive mode like with the explicitly WASAPI devices, so I’d guess that it’s WDM. If that’s the case, does Roon just have to send off the audio stream (possibly resampled) to the Windows built-in mixer?

Edit: With enough fiddling of the settings, I can get reliable playback through certain WASAPI devices in either exclusive or shared mode, albeit with quite a bit of audio crackling. I have the RME driver exposing 3 WDM devices, the first of which I use for my main output, and it seems that this is the one which doesn’t work with Roon. If I change my default system output in Windows to the 2nd or 3rd WDM device instead, Roon will happily play back through the System Output without any issues, crackling or otherwise. I’ve checked that all my settings are identical between all the possible outputs, so I don’t know what’s causing the 1st WDM device to malfunction.

Edit 2: I just restarted my computer and now none of the WDM devices are working as the default output for System Output again…

5

Hi @Abel_Aebker,

Thank you for your patience.

Here’s what we can see from logs:

If I’m understanding your description correctly, the system mixer is set to 48khz and you’ve set this device at the default Windows sound output. In the logs we’re examining from August 10, the System Output Zone is Wasapi and Exclusive Mode is disabled.

Playback errors and unnatural stoppages accumulate whenever content plays at 44.1khz or any sample rate other than that dictated by the system mixer, 48khz. Specifically, RAATServer receives a format_not_supported response from driver and attempts to resend the command. After enough failures accumulate, the UI indicates “too many failures.”

Crackling during playback with WDM (with DSP disabled) usually indicates one of two things:

  1. sample rate differences between Roon and different apps (system notifications) that are also use kernel streaming.
  2. processing limitations or buffer issues. Try increasing the sample buffer size.

On each RAATServer startup in logs, Roon is first identifying the ASIO-controlled instance of the RME interface. Please share a screenshot of your Audio tab in Roon Settings and we’ll proceed from there.

7

Thanks @connor for the help!

Today I tried setting the Fireface USB driver to a 2048 sample buffer and it doesn’t improve the playback through the Roon System Output device. I normally am able to run at least two ASIO applications in parallel with several VSTs active on each without any issues at 256 samples, so I’d be surprised if this was a problem.

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This is the configuration I had when I got these errors (repeated several more times for each), showing an error with playback of both 44.1kHz and 48kHz content:

08/14 09:18:21 Trace: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  GOT [27] {"request":"setup","format":{"sample_type":"pcm","sample_rate":44100,"bits_per_sample":16,"channels":2,"sample_subtype":"none"}}
08/14 09:18:21 Trace: [RAAT::System Output] [output/wasapi] output setup: format is pcm 44100/16/2
08/14 09:18:21 Warn: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  setup failed: RAAT__OUTPUT_PLUGIN_STATUS_FORMAT_NOT_SUPPORTED
08/14 09:18:21 Trace: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  SENT [27] {"message":"RAAT__OUTPUT_PLUGIN_STATUS_FORMAT_NOT_SUPPORTED","status":"UnexpectedError"}
08/14 09:20:06 Trace: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  GOT [28] {"request":"setup","format":{"sample_type":"pcm","sample_rate":48000,"bits_per_sample":16,"channels":2,"sample_subtype":"none"}}
08/14 09:20:06 Trace: [RAAT::System Output] [output/wasapi] output setup: format is pcm 48000/16/2
08/14 09:20:06 Warn: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  setup failed: RAAT__OUTPUT_PLUGIN_STATUS_FORMAT_NOT_SUPPORTED
08/14 09:20:06 Trace: [RAAT::System Output] [lua@00000000268660E8] [127.0.0.1:59959]  SENT [28] {"message":"RAAT__OUTPUT_PLUGIN_STATUS_FORMAT_NOT_SUPPORTED","status":"UnexpectedError"}

I don’t see any indication here of a sample rate conversion for the 44.1kHz signal, but I’m not sure if that information would show up in the RAATServer logs or elsewhere. Perhaps concerningly, it looks like it’s always trying to playback with 16 bits per sample (the source for the 48kHz was a 48kHz 32 bit file from Qobuz, yet it still reports 16 bit in the logs). Not sure if this is a meaningful problem though.

8

Hi @Abel_Aebker,

We’ve looked into this further and can provide more clarity.

Here’s what’s happening:

  1. Roon loads the ASIO driver first unless the Wasapi non-exlusive Zone was actively playing previously, since it’s the default driver for this device
  2. Roon only releases the output channels used by ASIO to another driver when RoonServer restarts. This is by design to retain control of an exclusive Zone. Thus why restarting temporarily relieves the issue for you.
  3. The team will investigate why Roon is not releasing the output from ASIO when you switch to the kernel streaming Zone for the RME UCX II. We’ll let you know the next step.

Thank you again for your diligent posting. The next step is on our end, but we’ll follow up as soon as we can.

10

Hi @connor , thanks for all your help so far! Looking forward to further updates.

11

Hi @Abel_Aebker,
We’ve created a ticket with our dev team to look into this further for you. We will get back to you when we know more.

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