DSP Plugin with USB DAC: Asus Xonar Essence STU - Mixer Error

I have been trying to get the DSP Plugin to work.

I have a Volumio v2.882 fully working with USB DAC: “Asus Xonar Essence STU”. Everything works fine: no volume control through the application though (mixer defaults to hardware). I use the volume knob on the USB DAC.
I installed the DSP Plugin v1.9.3 and made a reboot.

After boot: The DSP-plugin had set Output Device as
“Dsp → Dsp → Xonar Essence STU”
This results in playback with no sound. I get the sound working again by changing the output device to “USB: Xonar Essence STU”.

I had no luck trying the demo filters
ALSA I/O: Could not set audio output parameters for “hw:Loopback”:
Failed to set sample format to S16_LE: Invalid argument.
Failed to init output device.
Failed to initialise digital audio interfaces.
brutefir.service: main process exited, code=exited, status=1/FAILURE

So I tried to change output to Factory_S32_LE and boot: no failures this time and sound OK on playback.
But no noticeable effect on the demofilters. Log show an error, when applying filters:

Fixed I/O-delay is 16384 samples
Audio processing starts now
info: VolumeController::SetAlsaVolumemute
error: Cannot get ALSA Volume: Error: Alsa Mixer Error: amixer: Unable to find simple control ‘PCM’,0
info: CoreStateMachine::pushState
info: CorePlayQueue::getTrack 0
info: CoreCommandRouter::volumioPushState
info: CoreCommandRouter::executeOnPlugin: volumiodiscovery , saveDeviceInfo
error: Cannot set mute ALSA: Error: Alsa Mixer Error: amixer: Unable to find simple control ‘PCM’,0

Any ideas about the root cause?
Is the Asus Xonar Essence STU not compatible?

you can look at this maybe it helps…

@dvo thanks but your link is not related to the problem.
@Jussi I suggest you to not spend your time with this version of Volumio and dsp plugin. I stopped working in it. Try Volumio buster beta and install Dsp4Volumio from the branch alsa_modular in my repo.

@balbuze i was just searching online and in this case not volumio, not mutch to find …
oke asla modular wil solve it. can the buster version run on 2.882? but that’s more your alley.

No problem…
Alsa_modular works only with Volumio buster. Yes it should work fine if they system works without Dsp.

Thanks, will do.

Buster with Alsa_modular seems to work with Asus Xonar Essence STU (with RPI 4b)! Great!

The new DSP plugin did not show any errors on the UI. Everything seemed to work. The demo filters had a noticeable effect.

Next step: learning to use REW and my brand new UMIK-1 microphone for some DRC basics :slight_smile:

Thank you @balbuze !

Sidenote: The log still shows the error for ALSA Mixer, but it doesn’t bother me anymore, because everything works fine (in stereo) & the DAC has a knob for volume. Log-snippet:
Audio processing starts now
info: VolumeController::SetAlsaVolumemute
Unable to parse:
Simple mixer control ‘PCM’,0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
error: Cannot get ALSA Volume: Error: Alsa Mixer Error: failed to parse output

Nice! Keep me in touch for your next test :wink: