Okay, just so you guys know I did do some research and have come up with a theory that this might work. I know I can fit 6.5 speakers in the front door, 5 1/4 in the rear doors and 6.5 in the rear deck with modification. Now can I actually run all these speakers with an aftermarket deck without an amp or do I need to get one to run it? At this point I have a 04 wrx with the premium upgraded speakers, stock sub under the passenger seat and the 6 disc changer. I'm no expert in sound systems but was hoping if I could get this to work without using an amp. Let me know your thoughts, thanks guys.

Ken

 

I believe most head units only have speaker-level outs for four speakers, not six. But the same goes for most amps, too. Now you can wire multiple speakers off of a single out, but it gets a little more complicated in terms of the ratings of the speakers, and you can quickly ruin the head unit and the speakers if you're not careful. And without an amp, you would be taking a step down in quality by increasing the speaker load by 50%. But you can do it with the right equipment and circuit design. Check out some of the car stereo websites like crutchfield for advice.

I guess the main question is why do you want to have both rear door speakers AND rear deck speakers? The deck speakers are in a better spot to fill the car with sound than the doors, and especially since they can be larger, I don't think you would notice (esp. from the driver's seat) if the doors are even there. I have a wagon, so no opportunity for the deck speakers, but all I hear from the driver's seat is the fronts. The rears just add a little fill, and serve the occasional passengers.

But if you want all six speakers (actually 8 with the front tweets), and you want it to be an improvement from what you have now, I would say an amp is pretty much required.

Good luck,

 

i'm running the front and the rear door speakers off of a 4-channel amp and running the rear deck speakers just off the head units.

After i moved the rear door speakers to the rear deck, the sound staging did improved but at the same time it felt like there was some sound gaps from behind the front seats where the rear doors speakers were.

 

along with an amp you would prob want a fuse at your batt (which i think u prob already have) and a multi fuse breaker in trunk at your amp especially if it is a NICE four channel trust me i hade a bad experiance l lets just say im out a $350 pioneer amp