Open baffle resources?

Hey all.

I've been reading about open baffle speakers and I've decided my next kit/project should be OB. Now I like to know why the speaker designer built his design in a certain way. This helps me learn and I is fun to know.

The biggest issue I'm having is understanding how the designers are picking their drivers. It seems like a high Qt value is needed for the bass woofer but I can't understand why.

Tldr version: anyone have resources regarding driver parameters for OB usage?