Again using your non-generalizable sample [due to small n] the results would likely only be audible if one was listening in a completely reflection free environment. Please note, in no way am I implying this data is usable, in fact it is most likely not, a far more reasonable approach would be doing exactly what I did in post 21 to minimize variation due to extraneous variables. For the sake of furthering this discussion I will still analyze this data. Also, if I have a chance will measure a larger driver I own this weekend in a more scientifically useful fashion. Please note the driver I plan on measuring has been shown to be extraordinarily linear and well designed it also happens to be far more robust than the HiVi D10.8.
Sealed with both cabinets modeled to the same exact size [blue is warm]:
Note the f3 difference is only 5Hz
Ported both cabinets are modeled exactly the same, including tuning frequency [blue is warm]:
Note the f3 difference is only 4Hz
In both cases response difference is minimal the only difference being a
slightly extended response. At the frequencies being discussed the room will have a far greater effect on response rather than this slight extension in f3. Please note the OPs hypothesis seems to have been revised [in post 31] such that smaller drivers are not actually effected by this supposed phenomenon making issues at higher frequencies moot.