This is how I fixed that on my 18.04 LTS:
I cloned a newer version of pulseaudio-equalizer from github and did the configuration. The way to do that is as follows:
$ cd ~/Desktop && mkdir tmp && cd tmp
$ git clone https://github.com/kernelOfTruth/pulseaudio-equalizer.git
$ cd pulseaudio-equalizer
$ cp -R share/pulseaudio-equalizer/presets/ ~/.config/pulse/
$ cp equalizerrc ~/.config/pulse
$ sudo cp -R share/applications/ share/pulseaudio-equalizer/ /usr/share/
$ sudo cp bin/pulseaudio-equalizer bin/pulseaudio-equalizer-gtk /bin/
$ cd ~/.config/pulse
$ touch ~/.config/pulse/equalizerrc.availablepresets
$ sudo chmod +x /usr/share/pulseaudio-equalizer/pulseaudio-equalizer.py
$ python /usr/share/pulseaudio-equalizer/pulseaudio-equalizer.py
Then at this point just enable the equalizer and apply the settings.
UPDATE: After a while (messing up with audio settings), I discovered that the equalizer never persists (enabling it misbehaved). That took me back to square 1.
To resolve that I downloaded pulseeffects and used it to trick pulseaudio-equalizer like this:
$ wget https://launchpad.net/~yunnxx/+archive/ubuntu/gnome3/+files/pulseeffects_1.313entornosgnulinuxenial-1ubuntu1_amd64.deb
$ sudo dpkg -i pulseeffects_1.313entornosgnulinuxenial-1ubuntu1_amd64.deb
Then I:
- Launched and enabled equalizer on pulseeffects,
- Launched and enabled pulseaudio-equalizer
- Exited pulseeffects
NOTE: Pulseeffects doesn't persist. I have no idea how, but it tricks pulseaudio-equalizer to persist. Beats me.