Car Stereos: speaker placement & sound quality, infinity speakers, mtx subs

Question
Hi!  I am a 40 yr. old woman who loves doing this stuff on my own, but I need alittle help.  I installed a Pir. head-unit, 4- JL audio 5x7 speakers, 1-JL audio 4/450 amp, 1- 500/1 amp, and a box enclosed 2-12" MTX subs in a 1999 Mustang. I added a pair infinity speakers yesterday. One where glovebox was, and one in driver panel by lock. Sounded great untill today, I added infinity 6x9's in rear deck with jl audio pair and now they overpower sound. I want more sound up front.  I also noticed one of my subs makes a weird loud abnormal vibration sound. I like my music LOUD! !  What can I do to achieve that. Plus can I move last pair of speakers to back side panels?  Thanks,  yea: Im old not dead.  Ha  Ha

Answer
Hi Stephanie,

You can put speakers whereever you want, really.

If you want to properly be able to control each speaker's level for optimal listening, though, I'd suggest getting a deck that has a per-channel volume control, or a good crossover.  Another thing to do would be to set up each speaker to only receive a signal within a frequency response range you want it trying to reproduce.  (Which a crossover will do.)

For example, your 5x7s might be rated for something like 50Hz, but aside from the fact that they'll never cleanly hit it, you've got subs to do that, so you can set the 5x7s to not reproduce anything below say, 150Hz.

Your best bet is to buy some hardware that will let you tune the sound the way you like it, whether it be a deck with a per-channel control, or a crossover, or some amplifiers with per channel gain controls.

Justin