[satfrat]

But Wilson does not use a smooth circle; it is a "star" cut. 
Mike

I wonder why 

Is it possible that the star shape makes for a more visual presentation that a mire circle and that might be more of a reason for Wilson to have used that design?   

[jimdgoulding]

I stamp a 2.5" wide hole in my fascias for my tweeters (1" domes).  In cases where a 1 or 1.5" dome is used I think this gives them room to do their thing without anything vital being grabbed.  Ribbons, too.  The star shaped surrounds that I have seen encroach more closely to the dome.  In this case, I expect it makes more sense.  I can't speak for Wilson but I use a very highly absorbent base material to start with.  I want customers to hear what I am hearing, first.

I posted a note from a member/customer in The Critic's Circle today.  And, another customer has replied, "I can't walk past my listening room without being pulled in".  I know what he means.  jim