Felt diffraction reduction advise


Never heard or tried them. Would try them on soft dome tweeters on floor stand or monitors. I have no problem with way system sounds now. Just found black wool felt in a Christmas box. Always been curious of speakers with felt with different cut out patterns. What inch thickness and pattern do I need to achieve any results good or bad? What will I hear when doing this?
paulcreed
Vandersteen use a deep 1/4” or so around the Model 7 MK II tweeter done, should be a photo out there somewhere.....
the cutout close to the dome is in a notched star pattern, maybe 20 cuts....

Vandersteen's is deep enough to act like a bit of a waveguide.

And yes, it does help. The felt seems to reduce re-radiation directly around the tweeter enhancing the speaker's disappearing act.
I have a question. If the creator of the speaker thought it needed felt, wouldn’t he or she have included it? It’s cheap and easy to apply. Or would it be added to change the highs in a unique situation?