Low audio volume with Behringer UMC204HD (F40)

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Hi!

After one of package upgrades I started having problems with my Behringer UMC204HD (2 input, 4 output channels) audio interface. The audio level on the output is very low, forcing me to go past the 100% limit in KDE mixer, what causes signal distortion. Both, the headphone and the playback outputs (channels A and B) are affected.
This problem seems to be related to one of updates, most likely to a massive update of plasma* packages at the end of November, however I’m not able to pinpoint a specific set of packages causing the problem.

Here’s what I tried to debug the issue:

  • Restarted the audio interface by disconnecting the USB cable.
  • Power cycled the computer.
  • Created a fresh account to make sure that it is not cause by my account settings.
  • Swapped UMC204HD to UMC22.
  • Connected UMC204HD to a different USB port.
  • Swapped amplified output from channel A to B.
  • Verified that none of system-wide audio system config files were altered from the distro versions.
  • Tested UMC204HD with a macbook.
  • Tested both interfaces with kernels 6.11.10 (current), 6.11.8, and 6.11.7.
  • Verified that both interfaces are handled by the same kernel drivers.

Here’s what I found:

  • Going over 100% in the mixer causes sound distortion, so it’s not just low volume setting.
  • UMC204HD works fine with the macbook, so the hardware is ok.
  • Channels A and B are affected.
  • The fresh account is also affected by this problem, so it’s not caused by local settings.
  • None of the config files showed up as altered in output of rpm -V
  • UMC22 is not affected by the problem.
  • Switching kernels does not fix the issue.
  • Switching interfaces in various combinations only changes reference counts for kernel modules.
  • All of this suggests that audio attenuation must be happening somewhere between volume control and kernel drivers.

UMC204HD is recognized as “Product: UMC204HD 192k”, “Manufacturer: BEHRINGER”, and UMC22 as “Product: USB Audio CODEC”, “Manufacturer: Burr-Brown from TI”

Has anybody experienced a similar problem?
Any ideas where to look for clues?

3

Had the same problem, i found out that in audio settings, in the configuration tab there is an option to change the HiFi output. Mine was at HiFi 2.0 as a default, changing it to HiFi 7.1 fixed it.

Hope this solves your problem