"Also, which speaker are we discussing?"
Just the smaller cones in general, as they relate to being a nice choice for DB's
"It’s all about the design."
Absolutely! there's no denying the awesomeness of an efficient speaker (regardless the size) when paired with an efficiently designed cab (again-regardless of the size)
Another thing that has recently been mentioned round here is the use of a high pass filter ala' the Thumpinator. I use one all the time, it's my constant end-of-chain charm.
I've been thinking about picking up an Fdeck HPF too. But I haven't been using the doghouse much lately (Norton custom Shen SB 100/innovation silver slaps/full circle/platinum pro) again, with the SFX at the end of the chain.
I also use a BSX Allegro. again it's been awhile.