TLDR - Factory dash speakers have a crossover point (HPF) of around 1800hz. They have a bennic capacitor 50wv 10mfd on them. The speakers themselves are 8ohm (important to know if you're swapping speakers but keeping everything directly ran by the head unit). So they have a crossover point of about 1800hz (ie. anything below that drops off, the rate of drop off I do not know or care to find). Speaker resistance affects output volume: Your replacements, if they're 4ohms, will be louder. A lot of people think "awesome! music louder!" Yeah well now the audio from your dash is maybe twice as loud as the audio from your doors and the frequencies below 1800hz that your doors are handling now feel underwhelming. Even worse for the rear doors because the rear channel is already neutered. You could slide down the treble in the audio tuning section on the head unit, maybe mids too? Not sure what the head unit considers mids and treble. Why knowing the crossover is important: If all you're doing is swapping dash speakers and your new dash speakers have a capacitor installed that crosses them over at a different frequency than 1800hz then you might not like the result. You may find there are spikes or dips in frequencies that affect music quality. Your front doors and dash are wired together: Keep in mind that the dash speakers (8ohm) are wired with the front door speakers (4ohm). I don't know if they're wired in series or parallel, but this is also something to keep in the back of your head.
It bought a pair of used Infinity 4022i for $80 since they seemed like a good deal. Finding 8 ohm speakers from even Crutchfield was impossible so I gave up. I wanted to install two of the Infinity speakers tomorrow since I'm in New England and it's beginning to get too cold to do this stuff as a hobby in my driveway. I also picked up some 6.5 inch Kicker Co-axials and had a set of new 5.25 Coaxials Alpine laying around. In addition, I have old Soundstream Reference 405 from decades ago that I wanted to go retro with when it got warmer. I just installed the CarABC Toyota Android Auto/Carplay kit that pipes blurry Android video into the Panasonic OEM unit via the the camera input, but again, it's getting too cold to do this stuff... Suggestions?
In the non-JBL, they're in parallel. The +/- signal leaves the radio, goes to a junction connector in the dash where they split, then each speaker gets a separate +/- from there. In the JBL, they're completely separate channels.
