nocturnal EG

ok...i just bought a 95 legend...everything is good...but that thing is, the stereo sounds like crap. it still has the stock deck in but im not sure about the speakers. from what i heard, the deck was programed with the 91 legend stereo code. k..the problem is, the music isnt as loud as it should be and there is no base whatsoever...i dont have subs...but u should still hear a little bass. so my question is...does anyone know how to fix this problem ?....do i need the 95 code ?...if so does anyone have it ?....any kind of information would help. thanks alot.