Good equalizer?

[parzzival]

does any one know of a good free equalizer? I want to get more bass out of my sub but I don't think its that necessary. and please keep it legal.

[TheMatrix]

Isn't there an option for your soundcard in one of the control panels?
I know that in PulseAudio(on Linux), you can set the gain to the sub(as well as all the other channels, of course).