Rear speaker problem in 99' Honda Prelude?

i just bought a 99' prelude and the sound is really tinny and high. i turned only the rear speakers on and they are super super quiet. it sounds like cell phone speakers. i think something is wrong with the amp cuz both of them do it. do i need a new amp, or is there something i can do to fix it? would it help if i bought a new stereo? cuz i want to do that so i can run my ipod through it