well my friends bro got me a good deal on a pioneer hu for my mach 460. problem is i think he didn't do the install right and he's out of town for the next couple weeks. anyways the system has seemed to have loss all of its bass and it seems very high pitched. a cousin of mine told me that he should've used some kind of adapter. anyways, what do i need to fix this? and will this be something i can do by myself considering i have never worked on a car stereo before?