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Nectar
Asked: 2018-04-12 02:58:18 +0800 CST

5.1 sound - rear left & right are very quiet - DOWNMIX

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I have a lot of 5.1 flac files. They play just fine, apart from not every channel will be downmixed at the right volume to the two speakers in my headphones while playing. This is the same no matter what player I use (vlc, ffplay, mpv, parole)

The front two, centre and LFE tracks are downmixed, and I hear them, but the rear two are very quiet.

A quick speaker-test shows this to be true.

How can I fix this? So far alsamixer has been totally unhelpful, as it never seems to display each virtual speaker, just a master volume, PCM, etc.

EDIT: I installed paman, and it shows how the sound goes from the sink input as "s16le 6ch 48000Hz" and somehow becomes "s16le 2ch 48000Hz", but during that process the channels are butchered and mixed wrong. What kind of malformed wizardry is this? Where can I find a mixer that will fix this?

http://storage4.static.itmages.com/i/18/0411/h_1523449183_4185382_2ff887d0ad.png

sound pulseaudio alsa

2 Answers

  1. New version using pavucontrol

    First install the app:

    sudo apt install pavucontrol

    Then call it from the launcher by typing the first few letters pav and selecting the icon. Follow the .gif below to click on the individual speakers and set their volume:

    pavucontrol individual speaker volume

    Original version not working

    Your question "What kind of malformed wizardry is this?" can best be answered with this command:

    $ grep channels /etc/pulse/daemon.conf
; default-sample-channels = 2

    Using sudo powers edit the file /etc/pulse/daemon.conf and change the line:

    ; default-sample-channels = 2

    to:

    ; default-sample-channels = 6

    Save the file and exit your editor. To restart pulse audio use:

    pulseaudio -k
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  2. Best Answer

    I had similar problems with a KDE Neon installation. The solution was installing the PulseAudio Manager (Do not worry, it uses a GUI):

    sudo apt -y install --no-install-recommends pavucontrol

    Then go to the Configuration tab, and test with the available sound configurations. You can also try setting the application/system volume in the Output Devices tab.

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