Ubuntu Version:
Kubuntu 25.10
Desktop Environment (if applicable):
KDE Plasma 6.4.5
Problem Description:
I am coming across and specific issue when launching games via Steam. I am an audio engineer so I have hooked up a MOTU 828 28-in/32-out USB Audio Interface (the latest model from 2024, not the older generations) to my desktop PC. The audio for most programs works perfectly fine, whether it be playing a video on my browser or speaking to/hearing from people on VOIP services such as Discord. I am also able to playback audio through my Digital Audio Workstation of choice (REAPER), as well as record straight to it without issue.
However, when I launch any game on Steam, the audio stream for the application is created in the sound manager, but paused and at zero output. Once the game fully opens (the application launches the window to the menu), the audio stream completely disappears and no audio is heard from in the game (this occurs with any game I launch via Steam, namely Hollow Knight and Deadlock as examples). I’ve confirmed this by checking audio sources via Helvum and there is no audio stream being sent to my outputs from these games.
Now what I find curious is the fact that this only occurs if my MOTU 828 is selected as the primary playback device in the Sound settings. If I enable the HD Audio Controller from my motherboard and select that as my primary playback device, when I launch the game and have it open to the main menu, the audio stream is both present in the System Sound settings as well as on Helvum, and is being correctly send to the HD Audio Controller. After this, I am then able to just swap from the HD Audio Controller to the Motu 828 and have audio playing back through the audio interface.
So, if my MOTU 828 is selected as the default playback device, any audio stream created from a game when they are initially launched are deleted shortly after the application opens. If I select a different audio device such as my onboard motherboard audio controller, the audio stream stays and gets sent to the selected playback device.
Relevant System Information:
MOTU 828 28-in/32-out USB 3.0 Audio Interface
Screenshots
Here is a screenshot of the sound mixer when I initially launch the game with my MOTU 828 selected as my playback device
And this a screenshot of the sound mixer after the game is fully running.
Here’s what it should look like when I have the HD Audio Controller selected as my default playback device (It’s being sent to the 828 Pro as I swapped it from the HD Audio Controller to my audio interface, which it now does by default, but ONLY when the HD Audio controller is selected as the default playback device)
What I’ve Tried:
As mentioned before, I can get playback to work through the interface but only when I have a different audio device selected as my playback device, and then swap to the interface after I have opened a game, but it doesn’t make sense that the audio stream for the game is just being outright removed when I use my MOTU 828.
I have also tried creating a combined output sink for all of my devices which did fix the issue, but I am unable to maintain it as a persistent playback device if I reboot the system, so it’s only as effective as my playback swap solution.