Would it be possible to split apart the wiring that feeds the top and bottom door speakers to make it so that the bottom 6.5" speakers receive the rear channel's full signal, and the rear 6x9s + front 3.5" speakers get the notch filtered signals? I've installed a sub, so I don't need the additional bass power that the regular front/rear swap provides. Currently with the channel swap, I get great sound output from the rears but terrible, tinny, low power output from the fronts. I believe it might be due to the 2 door speakers sharing the combined power of a single channel (per side), the notch filter (although to me it sounds much much higher than the 70hz cutoff that it should be), or perhaps frequency cancellation due to having replaced the components with coaxial 2-way and 3-way speakers. I know I should probably just replace the fronts with better components with a crossover network, but since I know the speakers I've got in there are capable of sounding SO much better and theyre practically brand new, I'd like to know if there's something I could do with the wiring that would move my sound stage to the front and give me a better overall balance.

 

I don't see why that wouldn't be possible. You'll just have to run new lines from after the X9331 to the lower speakers in the doors.

-Use the existing wire to connect the upper speakers with the filtered line.
-Piggyback off of the line going to the rear speakers on the unfiltered line.
-Run the new wiring along the existing wire that goes to the doors to connect to the lower speakers.

You should now have the Rear channel on the 6.5's and the 6x9's, and the Front channel on the 3.5's...

Keep in mind that this will reduce the sound output of the Bluetooth audio as it will only be pushed to the front channel.