I just replaced my full range 6x9 rear speakers with aftermarket 4 way 6x9s and it sounds tinny.?

Question

Do i have something hooked up wrong?

Answer 1

You may have your speakers wired out of phase.  Try adjusting the balance on your head unit, all the way to the left or right.  If it sounds better with only one speaker playing than with both playing, then switch the positive and negative connections on ONE of the two speakers.

Answer 2

either wired out of phase, or you bought some crazy 6x9 with 3 extra tweeters than what you were used to and now realize that nobody needs that many tweeters in a car?  seriously, thats just stupid.