How to Set Audio to Mono on a 3.5mm Jack in EndeavourOS with KDE and ALSA

[elphio]

Hello everyone,

I hope someone can help me with an audio issue I’m facing on my EndeavourOS-powered PC. I have a 3.5mm jack to which I connect stereo headphones, but I would like the audio to be in mono as I only use one ear of the headphones. This way, I can avoid missing out on audio from one channel.

I’m using the KDE desktop environment, and I believe ALSA is the audio system I have by default (I haven’t made any changes during the installation).

I’ve looked through the audio settings in KDE, but I couldn’t find an option to enable mono audio. Does anyone know how I can configure my system to achieve this?

Thanks in advance for any advice or suggestions!

[emk2203]

If you didn’t change anything at install, you should have pipewire as the audio system.

What is the result of LANG=C pactl info | grep -i "Server Name"? If it has something like Server Name: PulseAudio (on PipeWire 0.3.83), do mkdir -p ~/.config/pipewire/pipewire.conf.d and then create a file mono-playback.conf in the new directory (cd !$) with the following content:

mono-playback.conf

context.modules = [
    { name = libpipewire-module-loopback
        args = {
            node.description = "Mono Playback Device"
            capture.props = {
                node.name      = "mono_output"
                media.class    = "Audio/Sink"
                audio.position = [ MONO ]
            }
            playback.props = {
                node.name      = "playback.mono_output"
                audio.position = [ MONO ]
                node.passive   = true
            }
        }
    }
]

Now restart audio with systemctl --user restart pipewire{,-pulse}.{service,socket}.

You should now be able to configure the new mono output with your standard DE tool.

Set the volume at 80%. It is dependent on the volume of the standard stereo audio. 80% makes sure that the volume is about equal to your stereo volume.

[elphio]

Thank you so much, emk2203!

You were absolutely right; I did indeed have Pipewire as the audio system. I followed your instructions, and it worked like a charm. I now have mono audio output!

Thanks for your assistance!

[emk2203]

You’re welcome. I am interested in this topic as well, having mono audio for the headphones-half-on case is a good idea. Good that you got it to work without further issues.