Finalcut pro X bass boosted audio export problems!

Please help! ok so i've been trying to bass boost a couple different songs using Finalcutpro X 10.0. Before export the song have perfect bass, my headphones shakes, and the bass is very clean, but when i export, it just sounds like crap. I can barely hear a thing. this has also happend to me on other bassboosting programs like Audacity, it's allways perfect bass before export, and extremly deorientated, and scurry bass after. why dosen't it export exactly the same as audio as my project have? It must have something with compressing and making the file flat under export or something, right? if anyone know of a sulution to this i really appreciate your help, thanks!