4 channel amp to power 6 speakers?

I'm using a RF P4004. The rear channels are running pioner 6x9s. In the front doors, I have a set of RF 5.25" and the stock tweeters because the car had factory premium sound and I never took them out. Can I just wire the tweeter in parallel with the 5.25's?

Is that RF 5.25 part of a component package that includes a crossover and tweeter, is it a coaxial that includes a tweeter, or is it a stand-alone midwoofer?Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

The 5.25 is a power series T152C. They are coaxials and take 60 watts rms.

You *could* wire them in parallel... although it would be fairly ill-advised...but sound would prolly come out of your stereo. Running them like that would have them seeing alot of power at frequencies they were *not* designed to play... nevermind that the impedence on that 'premium' factory speaker might be something really weird and could concievably (but prolly not) damage ur amp when wired with a standard 4-ohm car speaker. I betcha if you just ran the coaxials straight you would find yourself rather happy with the sound.. my sense of things is that wiring another tweeter like that to a coaxial playing (mostly) full range would give nothing but a moderate amount of extra volume and probably not sound very good doing it."I'm finished!" - Daniel Plainview

S. Kephart and others have pointed out that using two sets of tweeters may result in less output rather than more, due to lobing issues caused by cancellation.  The 5.25's already have crossed-over tweeters, so you should leave the factory tweeters out of the setup.  It's not the point of whether it is possible to parallel them with the 5.25s, rather it's whether it makes any sense to do so.  It doesn't.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

You will get much better sound if you sell the current 5.25 coaxial, and get a true 5.25 or bigger component set that has a mid-range woofer, crossover and a tweeter. You can mount the new tweeter in the stock location if you want. Or put a double-sided tape to the back of it, with the music playing, move it around to find the spot that sounds best to you, cut a hole and mount the tweeter there. Most of factory un-crossovered tweeters are insignificat, mainly because they were designed to run in-line with stock mid-range speakers, they were thrown the same frequencies as the mids but not able to produce much music out of it and instead, mostly just noise. If you get a quality component system, you can test it by hooking up the crossovered speaker leads to the factory tweets, and then to the component tweets, it will be an enlightening experience.