June 30th 2009 I wrote about an equalizer-plugin for Rhythmbox which then was just about the only decent thing available. It now seems that that plugin isn’t being worked on anymore. Luckily we have people like Christopher Kruse from http://www.cornerofseven.com. :) He has now released version 1.3 of his Rhythmbox equalizer-plugin, which you can find at http://rbeq.googlecode.com/.
tar -zxvf rbeq-1.3.tar.gz -C ~/.gnome2/
Head on over to http://cornerofseven.com/blog/2010/02/rbeq-1-3-now-with-presets/ for the main post. Thanks Christopher!
And of course, a screenshot of the plugin: