Computer makes digital noise when working

r7l · Tux's lil' helper Joined: 16 Feb 2019 Posts: 89

I got a Thinkpad X1 Nano and audio does work. But i can hear my computer working.

If there is no audio being played from any kind of program the sound will remain silent. No matter what the computer is doing. It starts once something is playing audio and doesn't matter if it's browser, audio player or anything else. The amount of noise varies according to the workload the computer has. Not just according to the CPU but also for downloads from network or writing to disk. The noise will not act according to volume but remain the same, no matter if the general volume is set to loud or not. The only way to not have it, is muting the entire device.

I am running sys-firmware/sof-firmware as this is required for the audio to work at all. Other then that i am running Gnome, pulseaudio and systemd on this machine. I have similar setups on other Thinkpads but this audio issue is only happening with this Thinkpad.

Is there any fix to this or is this driver / hardware related?

szatox · Advocate Joined: 27 Aug 2013 Posts: 3150

My guess is it's hardware.
Builtin audio devices have been known for picking all the EM noise around them. This said, it is not "normal" or "to be expected" with modern hardware. Unless you plugged a radio transmitter (wifi, gsm) right next to your mic; these things dish out an absurd amount of power.

Anyway, boot it from any liveCD and see if the problem persists. If it does, report the issue to the manufacturer.

NeddySeagoon · Posted: Fri Nov 05, 2021 6:02 pm Post subject:

r7l,

That the noise does not change with the volume control is useful information.
It tells that the noise is being added after the control.

Describe your entire sound system.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

r7l · Tux's lil' helper Joined: 16 Feb 2019 Posts: 89

NeddySeagoon,

there isn't much of a sound system. Since this laptop is pretty portable with only 3 ports (2x USB-C, 1x Audio Jack) i am using it as a tiny mobile workstation. So the only things being connected is power or one of my 2 headsets. Usually i am using a older Samsung phone headset when talking to people and otherwise i am using a Sennheiser headset when listening to music or anything else. The noise is on both of these headsets and both are wired and connected to the audio jack. I am not much of a bluetooth fan.

Maybe you can see in this picture that the headphone jack is directly next to the USB-C ports powering this laptop. At first, i thought it might be an issue because of the power flow being so close but the issue remains if the laptop is running on battery.

Other then that, it's set up as described. Gentoo Sources kernel, sys-firmware/sof-firmware, systemd, Gnome with pulseaudio.

I am barely using the internal speakers but i've just noted that there isn't any noise when using them. The only issue with those speakers is that they sound flat. But that's something i would expect by design. But since the speakers do not have this issue, it might actually be hardware related?

Here is pacmd list-cards:

NeddySeagoon · Posted: Fri Nov 05, 2021 10:27 pm Post subject:

r7l,

Do you have wireless or wired keyboard and mouse, or do you use the build in keyboard and pointer?
Its been known that allowing the mouse and keyboard cables to be close to the analogue audio cables can cause issues.
Keep the headphone cable away from other cables.

Test with the external PSU disconnected from the mains.
Its a switched mode PSU and will generate electrical noise whenever its powered up. Its not enough just to unplug it from the laptop,

Your BIOS may have some "Spread Spectrum" options. If they are there, enable them.
Its a trick to spread the electrical noise generated by the PC clocks over a wider range of frequencies that they would otherwise be.
This in turn can reduce electrical noise getting into other things.

Can you connect an external display and turn off the laptop display?
That's hardly a workaround but the backlight control is a source of noise as is the display refresh.
Does changing the display brightness or refresh rate (with a static image) affect the noise.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

sdauth · Guru Joined: 19 Sep 2018 Posts: 572 Location: Ásgarðr

This looks like this https://libreboot.org/docs/misc/#high-pitched-whining-noise-on-idle-in-debian-or-devuan
Try to use powertop as described in the link.

Very common with Thinkpad.. A bit crazy to see it is still happening with recent models though. (Using powertop fixed the issue on my X200 & T400)

r7l · Tux's lil' helper Joined: 16 Feb 2019 Posts: 89

Sorry, had a busy weekend no time to look into this. Just tried what was suggested.

sdauth,

i've followed your suggestions. When using a live image the effect remains as i've had the same noise when using latest Ubuntu and playing some music.
Powertop also didn't change anything.

NeddySeagoon,

i am only using the build in keyboard and trackpoint. And this noise remains no matter if PSU connected or running from battery. I've also tried to find the BIOS setting you've suggested. But there is nothing of that sort and i haven't seen such an option in any Thinkpad BIOS before. But maybe i've just overlooked it.

Changing the brightness of the internal display doesn't change anything. But i've connected my external display (usually i don't) and it instantly recognizes it as HDMI output and starts playing there. There is no noise on the monitor and this doesn't surprise me after i've found out that there is also no noise on the internal speakers.

All in all, it seems as if the problem might actually be a hardware issue with how the audio jack is wired (or to close) to some other stuff. For now it seems as the only way to get around this issue might be a non wired bluetooth headset.

Thanks for your help anyways.