[SOLVED] Sound plays through speakers regardless of what sink is selected

[mogplus8]

I've searched through a lot of posts about sound problems, but I couldn't find anything like this.
My speakers work fine when I select "line out - built in audio" in pavucontrol or in the sound settings. But if I select "headphones - built in audio" the sound still comes out of my speakers, and not out of my headphones. The volume changes depending on which one I select, as each one has a different volume setting apparently, so it seems like everything is working correctly. It's just that the sound that should be sent to my headphones is sent to my speakers instead. I didn't have this problem before I upgraded to 20.1 Vera, so I don't think it's a hardware problem.

All advice gratefully received.

Code: Select all

ian@Mintian:~$ inxi -Fxxx 
System:
  Host: Mintian Kernel: 5.15.0-69-generic x86_64 bits: 64 compiler: gcc
    v: 11.3.0 Desktop: GNOME 42.5 tk: GTK 3.24.33 wm: gnome-shell
    dm: LightDM 1.30.0 Distro: Linux Mint 21.1 Vera base: Ubuntu 22.04 jammy
Machine:
  Type: Desktop System: Hewlett-Packard product: HP Compaq Pro 4300 SFF PC
    v: N/A serial: <superuser required> Chassis: type: 3
    serial: <superuser required>
  Mobo: Hewlett-Packard model: 2ADE v: 1.0 serial: <superuser required>
    UEFI: AMI v: 8.12 date: 09/04/2013
CPU:
  Info: quad core model: Intel Core i5-3470S bits: 64 type: MCP
    smt: <unsupported> arch: Ivy Bridge rev: 9 cache: L1: 256 KiB L2: 1024 KiB
    L3: 6 MiB
  Speed (MHz): avg: 1925 high: 2264 min/max: 1600/3600 cores: 1: 1685
    2: 1901 3: 2264 4: 1850 bogomips: 23147
  Flags: avx ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
Audio:
  Device-1: Intel 6 Series/C200 Series Family High Definition Audio
    vendor: Hewlett-Packard driver: snd_hda_intel v: kernel bus-ID: 00:1b.0
    chip-ID: 8086:1c20 class-ID: 0403
  Device-2: Focusrite-Novation Speedio type: USB
    driver: hid-generic,snd-usb-audio,usbhid bus-ID: 2-1.5:4 chip-ID: 1235:0002
    class-ID: 0300 serial: 20220211
  Device-3: Sunplus Innovation AAPDQT-0622-W type: USB
    driver: snd-usb-audio,uvcvideo bus-ID: 2-1.6:3 chip-ID: 1bcf:2cb4
    class-ID: 0102 serial: 01.00.00
  Sound Server-1: ALSA v: k5.15.0-69-generic running: yes
  Sound Server-2: JACK v: 1.9.20 running: no
  Sound Server-3: PulseAudio v: 15.99.1 running: yes
  Sound Server-4: PipeWire v: 0.3.48 running: yes

[AZgl1800]

I occasionally have the same problem with BT headphones.

I just bring up the Sound App, and click back and forth between the two options, and usually the 2nd instance fixes the issue.

[mogplus8]

After a lot of searching around the net I finally found the solution. It seems auto-mute in alsamixer had somehow been disabled. Auto-Mute is the function that automatically turns off the speakers when headphones are plugged into the headphone jack, and turns them back on again when the jack is removed.
The solution is to start alsamixer (by entering the command "alsamixer" in the terminal), select your audio card (F6), then scroll across (right arrow) until you see Auto-Mute. If you can't see Auto-Mute, keep pressing right arrow until you see it (I didn't find this out until much later...). Then set it to something other than disabled.
I also came across the recommendation to enter the command "amixer -c<N> sset "Auto-Mute Mode" Enabled". where <N> is the number of your audio output device. This didn't work for me, it returned an error saying "Auto-Mute Mode" was an unknown command. Your mileage may differ...
After correcting the Auto-Mute setting (however you do it) then do "sudo alsactl store" to ensure the setting is still correct after a reboot.