Just a quick update on Freeverb3 in Gentoo: media-libs/freeverb3-3.0.0 is now unmasked and working with media-sound/audacious-3.3.4, the latest Audacious in Gentoo. Give it a try :-)

PS: The theme on the screenshot is Radience known from Ubuntu or x11-themes/light-themes in Gentoo.