Distorted audio on 25.10 with USB CM106 sound device

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1

Hello,

I’m running 25.10 with an external USB sound device detected by Ubuntu as a “CM106 Like Sound Device”. It’s a cheap StarTech ICUSBAUDIO7D: https://www.startech.com/en-ca/cards-adapters/icusbaudio7d

The sound works fine after a reboot. I didn’t have to install any drivers, it worked out of the box. After a few days, however, the sound from one channel (2-channel stereo setup) becomes distorted. The other channel is fine. The only solution I’ve found is to reboot, after which it’s fine for another few days.

I’ve tried restarting pipewire, wireplumber and pipewire-pulse but no effect:

systemctl --user restart wireplumber pipewire pipewire-pulse

Any ideas?

Thanks!

2

Just some thoughts:
Maybe it’s a hardware issue? Did you try disconnecting the external sound device and reconnecting again after some (> 30) seconds when the distortion occurs?
Did you use this device before switching to Ubuntu? If so - did it work properly under same conditions? What about the speaker system?

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3

Thank you,

The same hardware (laptop PC, USB sound device and speakers) has worked fine in Windows 10 and 11 for years. The problem seems to be Linux-specific. The speakers are connected to the sound device using SPDIF optical - in fact, that’s why I need the sound device, since my laptop does not provide an optical out for my speakers and I prefer that to analog.

The laptop’s internal speakers always work fine without any distortion.

I haven’t tried unplugging and reconnecting the USB sound device; will do so tonight. Even if that works, however, I’d prefer not having to do that every few days. The fact that it works fine after a reboot makes me think there must be a setting somewhere that I can tweak. I just don’t know enough about sound in Linux to troubleshoot and fix this, unfortunately. Most of my Linux experience to date (before switching over my desktop) has been managing headless servers, where I didn’t care about sound.

Thanks

4

Not necessarily.

It actually makes (a lot) more sense what @g-schick is thinking of when he asked you to try simply disconnecting and reconnecting, instead of rebooting. An electronics engineer will be able to explain the reasons. Hint: What you’re convinced is a Linux-specific can very well be age-specific.

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5

OK, I’ve confirmed that unplugging and reconnecting the USB cable to the sound device resolves the issue temporarily. Not sure where that leaves me in terms of a permanent solution, however. It would be a big coincidence if the hardware started being flaky exactly when I switched my PC from Windows to Linux. Possible, but unlikely, which is why I don’t think it’s the hardware. In fact, it still works fine in Windows across multiple suspend & wake cycles (I dual-boot my PC and still have my Windows partition).

6

Switching OS you likely also changed how external hardware is handled.

With every information you provide you may get hints that get you closer to a possible solution.

Again some thoughts:
Do you suspend Ubuntu like Windows? Or do you keep Ubuntu on all the time?
How does your Windows handle USB power while suspended? Does Windows cut the USB power while suspended (and restart (and reset) the device on wake)?
If you suspend Ubuntu: How does your Ubuntu handle USB power while suspended? Does Ubuntu cut the USB power while suspended?

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7

Thanks,

I suspend both Ubuntu and Windows. In both cases, power to the USB sound device is interrupted; I can confirm this since the device has a power LED that turns off when the computer suspends.

8

Once the issue occurs, run:

dmesg | tail; lsb_release -a; uname -a

what is the full output please?

9

If you want to check for differences in settings and drivers you should collect data while the system is working properly and while the distortion is occurring. I doubt there will be (significant) differences.

You may try to restart the device using software but I do not know how to do that. I’m sure somebody else can help you with that. If restarting the device does work and solves your problem you probably can add a script that’s run on wake.

10

Unfortuntely I don’t think there’s anything useful here:

$ sudo dmesg | tail
\[617051.835125\] audit: type=1400 audit(1769190500.170:1356): apparmor=“DENIED” operation=“connect” class=“file” profile=“/usr/bin/wsdd” name=“/run/uuidd/request” pid=5036 comm=“python3” requested_mask=“w” denied_mask=“w” fsuid=1000 ouid=0
\[617054.971683\] audit: type=1107 audit(1769190503.305:1357): pid=2301 uid=996 auid=4294967295 ses=4294967295 subj=unconfined msg=‘apparmor=“DENIED” operation=“dbus_signal”  bus=“system” path=“/org/freedesktop/login1” interface=“org.freedesktop.DBus.Properties” member=“PropertiesChanged” name=“:1.4” mask=“receive” pid=51198 label=“snap.thunderbird.thunderbird” peer_pid=2365 peer_label=“unconfined”
exe=“/usr/bin/dbus-daemon” sauid=996 hostname=? addr=? terminal=?’
\[617072.914841\] audit: type=1107 audit(1769190521.248:1358): pid=2301 uid=996 auid=4294967295 ses=4294967295 subj=unconfined msg=‘apparmor=“DENIED” operation=“dbus_signal”  bus=“system” path=“/org/freedesktop/login1” interface=“org.freedesktop.DBus.Properties” member=“PropertiesChanged” name=“:1.4” mask=“receive” pid=51198 label=“snap.thunderbird.thunderbird” peer_pid=2365 peer_label=“unconfined”
exe=“/usr/bin/dbus-daemon” sauid=996 hostname=? addr=? terminal=?’
\[617086.808495\] audit: type=1107 audit(1769190535.142:1359): pid=2301 uid=996 auid=4294967295 ses=4294967295 subj=unconfined msg=‘apparmor=“DENIED” operation=“dbus_signal”  bus=“system” path=“/org/freedesktop/login1” interface=“org.freedesktop.DBus.Properties” member=“PropertiesChanged” name=“:1.4” mask=“receive” pid=51198 label=“snap.thunderbird.thunderbird” peer_pid=2365 peer_label=“unconfined”
exe=“/usr/bin/dbus-daemon” sauid=996 hostname=? addr=? terminal=?’
\[617094.233160\] audit: type=1107 audit(1769190542.566:1360): pid=2301 uid=996 auid=4294967295 ses=4294967295 subj=unconfined msg=‘apparmor=“DENIED” operation=“dbus_signal”  bus=“system” path=“/org/freedesktop/login1” interface=“org.freedesktop.DBus.Properties” member=“PropertiesChanged” name=“:1.4” mask=“receive” pid=51198 label=“snap.thunderbird.thunderbird” peer_pid=2365 peer_label=“unconfined”
exe=“/usr/bin/dbus-daemon” sauid=996 hostname=? addr=? terminal=?’
\[617241.379701\] Lockdown: systemd-logind: hibernation is restricted; see man kernel_lockdown.7

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 25.10
Release:	25.10
Codename:	questing

$ uname -a
Linux nick-laptop-linux 6.17.0-8-generic #8-Ubuntu SMP PREEMPT_DYNAMIC Fri Nov 14 21:44:46 UTC 2025 x86_64 GNU/Linux

However, I was able to reset the USB device as @g-schick suggested:

$ sudo usbreset "USB Sound Device"
Resetting USB Sound Device ... ok

Then the distortion in the sound was gone! So a workaround is to add a script that runs on wake as he suggested. Thank you!

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