Does that thus mean you are of the same opinion that the 'type' of speaker reproducer is irrelevant - if each type has the same spectral effect (hopefully none- but that is also irrelevant) on the input signal?

This should also mean that the output SPL's are also equal because the ear is more sensitive to lower and upper frequencies at higher volumes (our friends Flethcer and Munson - who have, btw, opened a chain of steak houses - alas - no ketchup).