Mumble (w/ Pipewire?) seem to require being in rtkit group

Haven’t diagnosed or bisected much, but since today my mumble client crashed at startup.

❯ mumble
This is Mumble v1.5.915
<X>2026-08-08 16:55:30.096 Loading settings from "/home/user/.config/Mumble/Mumble/mumble_settings.json"
<D>2026-08-08 16:55:30.113 PulseAudio 17.0.0 from libpulse.so
<X>2026-08-08 16:55:30.117 PipeWire 1.6.8 from libpipewire-0.3.so
<W>2026-08-08 16:55:30.127 Theme: "Mumble"
<W>2026-08-08 16:55:30.127 Style: "Lite"
<W>2026-08-08 16:55:30.127 --> qss: ":themes/Default/Lite.qss"
<W>2026-08-08 16:55:30.128 Locale is "fr_FR" (System: "fr_FR")
<W>2026-08-08 16:55:30.165 Database SQLite: "3.53.3"
<W>2026-08-08 16:55:30.184 Updating application palette
<W>2026-08-08 16:55:30.193 GlobalShortcutX: Using XI2 2.4
<W>2026-08-08 16:55:30.219 QMetaObject::connectSlotsByName: No matching signal for on_qtvUsers_customContextMenuRequested(QPoint,bool)
<W>2026-08-08 16:55:30.219 QMetaObject::connectSlotsByName: No matching signal for on_muteCuePopup_triggered()
<X>2026-08-08 16:55:30.227 Trying to restore window state and geometry
<X>2026-08-08 16:55:30.231 Successfully restored window state and geometry
<W>2026-08-08 16:55:30.241 Wayland does not support QWindow::requestActivate()
<W>2026-08-08 16:55:30.243 AudioInput: Opus encoder set for high quality speech
<W>2026-08-08 16:55:30.243 AudioInput: 40000 bits/s, 48000 hz, 480 sample
<W>2026-08-08 16:55:30.246 AudioInput: Initialized mixer for 1 channel 48000 hz mic and 0 channel 48000 hz echo
<W>2026-08-08 16:55:30.247 AudioOutput: Initialized 2 channel 48000 hz mixer
<W>2026-08-08 16:55:30.265 Zeroconf: Third-party browser API reports error -65537
[1]    27366 killed     mumble

Fumbling around I added my user to the rtkit group which solved the issue, and is reproducible on my setup. Will post if I have more information.

Might be related to this issue:

If you don’t want to keep your user in the rtkit group:

In Mumble’s configuration file (probably at ~/.config/Mumble/Mumble/mumble_settings.json) there should be two keys: "input_system" and "output_system". If you assign both of those keys to "PulseAudio" (and you have PipeWire<->PulseAudio compatibility configured in Nix), then Mumble should not crash. Here’s what that looks like in my mumble_settings.json for reference:

{
    "audio": {
        "echo_cancel_mode": "Disabled",
        "input_system": "PulseAudio",
        "loudness": 3749,
        "noise_cancel_mode": "Speex&RNN",
        "output_delay": 1,
        "output_system": "PulseAudio",
...

(You can probably change it in the GUI but personally I always get lost in there.)

If you need to enable PipeWire’s compatibility with PulseAudio you can do that in your Nix configuration like this:

services.pipewire = {
  enable = true;
  pulse.enable = true;
};
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