Guess I'm pretty spoiled that I was able to fairly easily run my own wire to all speakers that way there's no doubt the polarity is correct.
They might say "don't try this at home" but nothing about not trying it at your friend's house.
This sounds very much like the problems we see with subs, even when EVERYTHING is absolutely correct we still need to adjust T/A or polarity or add an all-pass filter to correct environmentally induced problems. Since the problem was with midbass speakers, it kinda makes sense.
I have my own wire ran to all speakers. I am not using any factory. Polarity is correct with the wire.
Ya, I think this is more about environment than anything else. I've had some interesting environment issues with the 14 F150. Even Justin Zazzi is confused as to why my speakers respond as if they are in an open field and not in a door that is fairly well deadened and sealed (CLD, CCF, MLV). Two different sets of speakers having the same issue leads me to think it is the environment.
2014 F150 Limited -> Kenwood DDX-9907xr -> Helix DSP.2 -> Alpine PDX-V9 -> SI M25 mki in Valicar Stuttgart Pods, Rear SB17's, Sub SI BM MKV's in MTI BOX. Alpine PDX-F6 -> SI Tm65 mkIV, SI M3 mkI in Valicar Stuttgart Pods