Arch Linux

Nova

Member

Registered: 2025-04-21

Posts: 14

Downmix system audio to mono?

I use my system with a pair of headphones, which I only wear on one ear. (This is just personal preference, wearing them on both ears feels weird to me.) The problem is, because they're headphones, my system audio is in stereo, which leads to me missing out on sound that only plays in one ear. Is there a way for me to make my system audio output as mono, so I can hear everything? I'm running KDE Plasma Wayland and Pipewire if that helps.

Last edited by Nova (2025-04-21 22:28:53)

espresso

Member

From: Pale Blue Dot, US

Registered: 2023-05-15

Posts: 62

Re: Downmix system audio to mono?

I can think of at least two approaches using PipeWire:

1. Minimalistic:

Pipewire Mono Playback Device: I have not tested this module myself, though I have used this directory for autoloading my own. Credit: Ali Tajelsir
This will create a virtual sink which can be selected in audio applet/settings, e.g. Plasma, pavucontrol.
Create a .conf (e.g. mono-playback.conf) in your $HOME/.config/pipewire/pipewire.conf.d/ directory with the following:

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
    }
  }
}
]

Restart pipewire service: systemctl --user restart pipewire{,-pulse}.{service,socket}
Pipewire docs on Virtual Devices: https://gitlab.freedesktop.org/pipewire … al-Devices

2. With a GUI:

https://wiki.archlinux.org/title/PipeWire#GUI refers to a few tools that are capable.

With EasyEffects (taking steps from 'geekley' with thanks):
  Output > Effects > Add Effect > Stereo Tools
  On Stereo Matrix tab, choose "Mono Sum L+R". "Stereo to Mid-Side" seems to work too.
  In Preferences, make sure to enable "Launch Service at System Startup".
  Optionally create presets for "Mono" and "Stereo" for convenience.

Let us know how it goes?

Last edited by espresso (2025-05-22 02:28:26)

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realroot

Member

Registered: 2022-04-24

Posts: 7

Re: Downmix system audio to mono?

I did not test this in Arch Linux, I found this topic when looking to how make the audio mono and I though to share what I found.

If I make a virtual sink I can select it as active sink but there is no audio, I wonder won't it need to use a real sink too somehow?

With easyeffetcs if I select `Mid-Side to Stereo` instead of `Mono Sum L+R` works.
I made a preset but when I load it I still need to change the value in `Stereo Matrix`, version `7.2.5`.
When connecting pc to a PA speaker that needs mono with a 3.5mm to 6.3 jack cable.

Last edited by realroot (Yesterday 18:26:12)

schard

Forum Moderator

From: Hannover

Registered: 2016-05-06

Posts: 2,527

Website

Re: Downmix system audio to mono?

Thanks for sharing, but OP hasn't come back to this topic since they posted it.

Mod note: Closing this old thread.

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