When I wrote the [autoEqualizer ](http://kde- apps.org/content/show.php/autoEqualizer?content=70509 “autoEqualizer”)plug-in for the Amarok (1.x) media player, to the best of my knowledge, there weren’t any media players with this feature nor were there any plug-ins.
Recently, I came to know that the Samsung Galaxy S ’s media player looks to be having the Automatic Equalizer functionality. Not sure if this player is specific to Samsung Galaxy S or the Android Platform in general.