Sound Equalizer for PC?

I am searching urgently for a programme (pref Freeware) that will auto equalise the songs I play (kind of like the Winamp plugin but for general PC sounds). I have ZARA Radio for the player adn need to use that but it doesnt support plugins! Do you know of an auto sound equalizer that I can install that will boost quiet tracks and tone down loud tracks in the output? THANKS! ! ! <><