Há uma publicação nos Fóruns do Ubuntu sobre como você pode usar o Equalizador do PulseAudio.
Vantagens:
- Configurable 15 band equalizer for PulseAudio;
- You can enable or disable equalized audio on-the-fly, without having to restart any running applications;
- Offers the choice of using equalized audio for the current session or permanently;
- No need to edit any configuration files by hand;
- User-customizable: you can use any LADSPA audio processing plugin (which can apply various audio effects beyond equalization);
- Packaged as a .deb file for easy installation;
- Graphical User Interface.