I ran

:~$ apt install pulseaudio-equalizer

An important detail, no icon was included in the Gnome Applications menu. I think it is important to fix it. So, I ran

:~$ qpaeq

and I received the error messages

Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
There was an error connecting to pulseaudio, please make sure you have the pulseaudio dbus module loaded, exiting…

I ran

:~$ pulseaudio

and I received the message

E: [pulseaudio] pid.c: Daemon already running.
E: [pulseaudio] main.c: pa_pid_file_create() failed.

So, I loaded the modules that were missing

:~$ pactl load-module module-equalizer-sink
:~$ pactl load-module module-dbus-protocol

and the equalizer opened and it didn't work (the sound wasn't changing).

Another important detail, why do theses modules are not loaded by default? I think this is another thing to be fixed.

I created the file ~/.config/pulse/default.pa with the lines

load-module module-equalizer-sink
load-module module-dbus-protocol

and I restarted to check. After the Gnome login the computer start to "freeze" by some seconds. In this condition, if I run

:~$ pactl list modules short | grep module-dbus-protocol

the terminal stops until I do Crtl+C.

If I try to load some module (module-equalizer-sink or module-dbus-protocol) I received an error message. So strange...

I restarted the computer again and the "freezing" happened again. So, in this way I deleted the file ~/.config/pulse/default.pa to come back to the early situation. I restarted and the "freezing" didn't happened again.

I tried another solution. I installed

:~$ apt install pulseeffects

and the equalizer was not working. Looking the pulseeffects FAQ,

I found a solution, to run

:~$ apt install lsp-plugins

Delete the folder ~/.config/gstreamer-1.0 (if it exists)

After to close the pulseeffects (if is opened) and run

:~$ dconf reset -f /com/github/wwmm/pulseeffects/

In this way, the equalizer of the pulseeffects worked.

3

2 Answers

Considering the comment of @mook765 above, I included the lines

### Modules for the Equalizer
load-module module-equalizer-sink
load-module module-dbus-protocol

in the end of the file /etc/pulse/default.pa. I checked the modules were not present and commented in the file originally.

I rebooted and I observed Gnome didn't "freeze" more after the login.

I ran qpaeq and the equalizer opened normally. I played an audio in the VLC and after in the Audacity to do some tests and the equalizer was not working.

I opened the Gnome Settings and I found a new device in Gnome Settings > Sound > Output > Output Device called FFT based equalizer on Built-in Audio Analog Stereo. When I selected this option the sound mute, so that, it didn't work. I pressed the Test button and there was no sound.

So, the pulseaudio-equalizer continue not working.

Highlighting, at last I guess there are two important points to be fixed in the Ubuntu 20.04 for pulseaudio-equalizer:

1. Include the qpaeq icon/shortcut in the Gnome Applications after the pulseaudio-equalizer installation.

2. Load the modules module-equalizer-sink and module-dbus-protocol and include than in the /etc/pulse/default.pa file after the pulseaudio-equalizer installation.

Beyond this, there is a third important point to be fixed: what is missing to the pulseaudio-equalizer to work? :)

3

Problem symptom: I faced a similar problem - after upgrading from Ubuntu 18.04.5 to 20.04.1, pulseaudio-equalizer could not be enabled:

$ pulseaudio-equalizer enable

PulseAudio Equalizer/LADSPA Processor 4.0 (29.01.2017)
... (10 lines omitted)
Equalizer status: [disabled]
Equalizer configuration status: [enabled]
Equalizer plugin: [mbeq_1197/mbeq]
... (3 lines omitted)

(That is, I tried to enable pulseaudio-equalizer but it remained disabled)

---

Problem crux: When I upgraded from Ubuntu 18.04.5 to 20.04.1, /usr/lib/ladspa/lsp-plugins-ladspa.so seem to have disappeared.

I realized this after seeing this thread about the equalizer in pulseeffects being greyed-out, where it turns out the OP was missing LSP.

---

Solution: Similar to the workaround where you installed lsp-plugins, I went to the LSP website, downloaded the latest lsp-plugins-ladspa, extracted lsp-plugins-ladspa.so and placed it in /usr/lib/ladspa/.

Afterwards, $ pulseaudio-equalizer enable works as expected, and I don't need pulseeffects.