If I switch the audio to the rear speakers there is zero bass
Sup with that ? Seems like all the bass comes from the driver and passenger door speakers. Is this normal ?
I missed which yr yours is. My 2011 had the Bose (non-Nav) system. The sub under the console is very small, maybe 6".
4years ago I replaced the all door speakers including the tweeder in the A-pillars. With same sized Infiniti branded speakers from Crutchfield for less than $400. Huge improvement including plenty of base aside from the anemic factory sub. Note that the factory Bose a 2 ohm which is more efficient needing less watts. I like high quality but not blasting sound. This was perfect.
Later I replaced the head unit so I'd have Apple car play. The speakers were the main improvement.
I just bought a '15 Yukon Denali with the Bose system. I'll do the same with the speakers. Sorry for the long post but this worked pretty good for not much money. Good luck!