Why 4 wires connected to Prime Advanced dash speakers?

WAG if speaker is powered Power/Signal if unpowered maybe Woofer or Tweeter and midrange.

 

Let’s just say ...
Wild Posterior Guess
Substitute Posterior with a 3 letter acronym beginning with “A”.

 

In the Prius Prime Plus, the front door speakers and the dash speakers are wired in parellel. The door and dash speakers are only connected to one set of outputs from the stock radio. So, for example, if you disconnect the wires to the dash speakers, the door speakers will not be powered from the stock radio either.

 

I was wondering has this been tested? Does that mean that only one wire is leaving the JBL amp towards the 3 front speakers?
Many thanks in advance for your help. I'm on a mission to find a full-range sound signal ;-).

 

I don't have the JBL system, so I can't confirm for sure on that system. But I have tested the Prime Plus and the dash speakers are definitely wired with the front door speakers. I tapped into the factory door speaker wiring just before those wires connect to the dash speakers and then ran that wire to an aftermarket amp since it seems no one has been able to get speaker wire through the front door. This is how I confirmed it.

 

RAIN 27 is correct.
I have a non-jbl system in my XLE and the dash speakers are feeding the front door speakers. The rear door speakers are on its own. I've tested it during my speaker replacement. Also, the system is front dash enhanced. meaning most of the power and sound comes from the dash speakers. Not only, the incoming Bluetooth phone sound is from the dash and front door speakers. After careful inspection, the system looks like a 2-way component between the dash acting as a Mid/High with a small BASS blocker and the door speakers as a full range driver. The rear door speakers are useless from the factory. LOL.
The dash speaker are mostly mid range so, I replaced the capacitor to a larger wider range so as to not eliminate the mids and replaced the door speakers to a 2 way component (6.5" with a 1" tweeter). Same for the rear door speakers. Even with a fader, and new drivers, the rears are pretty useless.
I plan to install a 5 channel line out adapter to erase the oem sound setting. Add a 4 channel amp and a powered 8" under the seat subwoofer. I think this will be more than sufficient sound system in a daily driver. Here are some pics of my tweeter location. door installation was the easier than the dash. Non- intrusive. On the door, there was no flat surface to mount the tweeter. so, I surface mounted with a tweeter that can be angled toward the headrest (Rockford Fosgate Punch). The rears can be flush mounted. not sure about the front tweeter. Flush mounted on the dash will be good. But more work. Also, the driver will point toward the windshield and non directional. Not as effective. The front pillars have airbag. so, not a good choice.

By the way, even wo. the new amp and a subwoofer will enhance the sound and bass for most people. But for me, I need a more balanced sound from front to rear as well as more bass.