Apeakers sound tinny.

hello all. i recently replaced all the speakers in the car as well as bypassed the factory amp. I'm using image dynamics chameleon 6.5's up front and infinity reference coaxed in the rear deck with a jl audio xd400. tied into the factory radio.i bypassd the amp by splicing the rca's into the signal output of the radio pre factory amp. the volume sounds clean and strong but one thing i am trying to decide is wether to tie in an audio control EQS. reason is all the speakers sound too tinny like there is too much midrange in the speakers.
any advice would be great. thanks.