I recently bought some new speakers for my 08 xB. For the front I got 6.5" pioneer 3 ways (220W max, 35W RMS). I hooked those up and they worked pretty well. The next day I received Pioneer 6.5" 4 ways (220W max, 50W RMS) for the back.
When i hooked up one of the speakers in the back, i thought it sounded terrible. There was no bass at all, and just a few mids. I thought maybe something was wrong with the speaker itself. I tested it using the amp I have for my sub, as well as a receiver I have in the house, and it works great. So, to my disappointment, the speakers are underpowered by the pioneer premium deck. (by the way, if you think i'm doing something wrong, please tell me!)
So now I figure I could install an amp for the speakers. My question about this is, would I have to run new speaker cable to every door, or can I use the existing wiring without much loss in quality?

 

ud want to use new thicker wire, the factory wire isnt that thick. Not to mention it goes from the headunit to your speakers. And you need to go from your amp to your speakers.

 

no, you don't need to run wire to each door, you can use the factory wiring, but it is much easier with an aftermarket head unit, because you can use the wiring harness.....instead of connecting the speaker outputs from the stereo into the adapter you connect the wires from the amp

this wire would work well... you can run all 4 speakers and remote turn on to the amps with it
http://cgi.ebay.com/20-9-WIRE-18Ga-C...QQcmdZViewItem

you also don't need thicker wire.... you can use this calculator, but for 18g with a 10ft run at 100 watts per channel at 4ohmsyou will get around a .37 db loss at the speakers....it will not be noticeable
http://www.bcae1.com/wire.htm


I have done it this way in cars before...much easier than running all new wire and unless you are running crazy serious power, very low impedance, or extremely long runs of wire you won't notice any signal loss.

good luck

 

awesome thanks for the detailed help!

I already have an amp for my sub, how would I take a split off the power cable running to that amp? Is the 8 guage cable I have enough to run all of this? (i have a 400W sub amp & the speaker amp will also be around 400W, maybe 500W (max power))

 

use that same wire calculator page...put in the size, length and efficiency of you amps and it will tell you...but most likely it will not, unless you are running class D amps, then it might be close, but I would probably still recommend going to 4g

 

So i was digging around in my premium HU's menus today. Turned the "car" selection to "flat" from xB and boom the rear speakers have their full range now, instead of being unbearably cut in the low and mid range.