Yeah I bought some Infinity kappas for the front and back and they sound great and all but less than of a week of me using them the front passanger speakers reps making a buzzing/rattling noise when it hits bass. I took the dash panel awl off to see if it was hitting something to be causeing the rattle n it looked fine and I held the speaker in my hand and keeps making the noise when I press on the speaker like rubber surrounding the buzz dosent happen. I also swapped the positive and negativ to see if I mabe missed up n put the wrong wires in positive n negative but didnt make a difference. It's only passanger that makes it so I'm thinking I might've of gotten a defective speaker speaker?? Since I have jut gotten them what do u guys think

 

Have you ruled out the vent ducts that route directly beneath the dash pad as the culprit?
There should be foam-rubber insualtion (preferably LOTS of it) to keep the hard plastic ductwork from vibrating.

 

You are sending too low of a frequency to your dash speakers. Unless the speaker has a large magnet or is over 6" in size, they suck at reproducing low frequencies. Try setting your dash speakers' crossover at 160Hz w/ a 18dB/octave slope, and drop the level of the speakers a point or two. If your setup isn't that advanced, just cut the level of bass going to your speakers until the buzzing stops.

I have JBL P462's in my dash and while the box says they are rated for 63Hz-20kHz, I could not get them to stop distorting until I set my crossover at 200Hz w/ an 18dB/octave slope, with my level set at 0, and now they sound fantastic. You don't really want dash speakers trying to reproduce low bass anyway, that's what a sub is for.