OK, reverse the leads to one of the front speakers - take positive and negative and switch them around, but only on one speaker.

 

If you do upgrade your speakers, which I would rec. because the stock IMO have terrible mid and treble, and they also distort... you will loose the thick bass they provide with an aftermarket 6 1/2 speaker.

I have an upgraded kenwood HU, and it made the stock speakers sound really good, with the windows up. If I drove with the windows down, I could't turn them up loud enough without crazy distortion.

I upgraded all 4 speakers and lost all the bass, than mounted two 8" subs under my seats.
Boom, complete system couldn't be happier.

Some pics are in this thread mid way threw the first page
https://www.evolutionm.net/forums/ev...-interior.html