Like raj55, I would replace all OEM dual-cone door speakers in non-Bose system with 4 6" 2-way coaxial speakers and leave the OEM tweeters alone. This would be an easier mod with better sound.
OEM A-pillar tweeters (Bose) seem to be not doing anything from my short test-drive experience, and raj55 said the same thing on non-Bose. It could be the design that the bass blockers only allowing very high frequency sound where most of us can't hear. Many people commented OEM A-pillar Bose tweeters are very-well made although I'm not sure the tweeters on non-Bose are the same.
Mazda uses all kind of different speaker connectors. Your PC-fan connector shown is for gen-1 CX-5 non-Bose dash speakers, but if my memory serves me correctly, OEM door speaker connectors on gen-1 CX-5 are different and speaker itself is even riveted to speaker adaptor/gasket. In any event some just torn up OEM door speakers and re-use the adaptor, others custom-made new adaptor to fit the after-market door speaker. Based on raj55's experience on gen-2 CX-5, the modification work on OEM speaker adapter/gasket is still needed like gen-1 CX-5, hence you may consider getting extra OEM speaker adapters if available for modification if you don't want to modify the original.
As for under-seat compact sub-woofer, or OEM Bose 5" sub, I think squibcakes said the best:
Appreciate your input but I'm well on my way.
OEM speaker in the door is a woofer, even if full range. It's just not a sub-woofer.
Agree that dropping in a coaxial and leaving the tweeter alone will be an easier mod, but dropping in a proper component set will no doubt sound better even on head unit power.
I've decided on my plan of attack:
Equipment:
- Polk DB6502 components in the front
- PAC AOEM-MAZ2 amp integration harness
- Kenwood KSC-SW11 under seat sub
Install:
- As long as the PAC works in the Gen2, I'll be placing that harness in line to the TAU. I'm betting its in the same or similar spot as previous models (but have not been able to confirm).
- Will mount the new Polk X-overs under / in the dash with the PAC. Chop into the PAC harness for speaker inputs from the TAU and outputs to the OEM wiring.
- Will sacrifice OEM woofer and cut-up to use as a mounting ring and for the harness connector as Raj did.
- Will abandon the OEM tweeter wiring and run new wires from A pillars to the new Pol X-overs.
This will get my gear installed without snipping or splicing a single OEM wire and will be 100% reversible if needed. Permanent mods will be to the A pillars (betting I'll have to cut to surface mount) and to the door speakers themselves, which will be destroyed.
Other benefit will be that I'll have RCA's for the sub instead of line-level inputs, and full ability to add further amplification if I'm not happy with how it sounds off the head unit.
I'm well-aware that the sub won't hit super deep or rattle windows. I'm not expecting or wanting that. What I am wanting is a little more than what the door speakers themselves can provide and be able to independently adjust the sound to my tastes (speakers vs sub adjustments).
Fingers crossed it all goes as planned.
Polk speakers are in my possession, when the PAC adapter arrives I can install them, then add the sub whenever it comes in.