Nice topics.
I like your idea of a separate "slamming" driver. Getting it to play well with the other drivers will be the challenge.

Bass impact is a good term. I missed the previous thread discussing slam. I also wish for the type of physical musical involvment you describe. My son plays drums. In the next room with the door closed you are safe. When you enter his small bedroom while he is playing you can feel a physical impact on your body.

My own rule of thumb which I am investigating is: For slam you need a baffle the size of a door.

I think that "slam" may have something to do with the transient response and the "coherence" of the waveform. For drivers on smaller baffles the "impact" wave is not focussed and is omnidirectional and smeared by all reflections. Open baffle is more directional but I still think size (of the baffle) matters.

Just my own thoughts. Keep up the good work and let us know how you go.

Regards Philip