I've always felt that there is something right about no dust cap. No real reason, but it seems inherently right to do away with moving mass that can be surplanted by a well designed grill covering the entire driver.
Lets face it, any number of drivers
with dust caps have vented pole pieces so dust is getting in one way or another, so as far as I can tell, its mostly about cosmetics.
The only time I can see it making sense is when you have a truly continuous profile convex cone like that used in the PB-13. The rigidity of the diaphragm would be compromised by the discontinuity of cutting it. Or is it just an oversized inverted dustcap for the cone behind?
I'm still not sure what the point of that ruddy great thing is in the middle of B&W drivers though?
Russell