surface area of sphere = 4*pi*rs^2
surface area of driver = 1*pi*rd^2
the ratio of sphere size to driver size is 4rs/rd.
For Dan’s Speaker, “R2,” with 3.25” drivers the ratio is 11.5
For Bubba, with 5.25" drivers the ratio is 15.25
the ratio should be at least 11.5
Relationship of speaker driver radius