[X4U] What to use to change freq response of MP3?

[Crandon David]

Hello Everyone,

I recently went to a great concert, Jason Bonham's Led Zeppelin  
Experience. At the conclusion of the concert you could go to a  
computer kiosk and download that nights actual concert in MP3 format.

I was pretty disappointed with the quality though. Specifically it  
was extremely bass heavy. I played it for the first time on my car  
stereo and had to use the bass control to decrease the amplitude by  
10db to get it anywhere near listenable.

I want to use a program of some sort to shape the frequency response  
to make it listenable.

Although I am an audiophile and know what I want it to sound like, I  
don't know how to get it there. Does anyone have suggestions of a  
program to use? I do have GarageBand 09, but have never used it.

Thanks everyone!