My current car has a rather strange speaker size arrangement. Currently, I am using an Android head unit sending sound to 6 speakers i.e.
- 2 x 3.5 inch coaxial speakers at the dashboard
- 2 x 6/9 coaxial speakers at the front door card
- 2 x 3.5 inch coaxial speakers at rear pillar (near to cargo door, it is an SUV).
- 1 Alpine active subwoofer at the cargo area

All of these speakers were already upgraded to JBL club series. After installing the speakers and subwoofer, I find the music too sharp and the bass is harsh (feels like not properly moderated, either too hard or too boomy...). The EQ in the Android head unit is a joke...

I am not planning to change to component speakers after already spending so much upgrading to same type/ size speaker but better brand. That leads me to considering amplified DSP (e.g. Alpine unit?). For my current set up, I am not sure if DSP will help and if 6 channel output is good enough?

In my mind, use 6 channel dsp to filter out high freq for coaxial at door card, and filter out low freq for smaller coaxial at dash and rear pillar… sort of ‘component’ style? Does it work that way?

I enjoyed good sound system but not too picky about it... e.g. I am happy with 50% of Volvo XC40 Harman Kardon level but don't have to go until Volvo XC60 B&W level.

Hope to hear your advice and suggestions.