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
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Have to say there is something to this. The circle cut out didn't work. Strips made into rectangle does change things for the good. Highs seem smoother, relaxed and more air and stage no loss of highs or feeling it was killing the sound. I had to stack 6 felt strips to make 1/2 inch strips to form the rectangle then made a lip on top and bottom totaling 9 strips to make the 3/4 inch lips. It's like the more felt I added the better things became which is the opposite results adding the circle cut out. I kind off copied the Dunlavy speaker Eric suggested, thanks Eric
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?

Of course, and some do, some don't. I think this is partially a matter of aesthetics, but also whether the designer even thought to experiment with it. I don't think felt will always be desirable, but I do think it's a simple experiment you can do.
It's no different in my mind than playing with cables or toe-in.

Excessively deep foam/felt though becomes something else. Then we get into waveguide like behavior. If you are taking that approach you are approaching speaker redisign so might as well start from scratch.

I think Duntech or Dunlavy's used this deep felt approach as well.

Best,
E
Cut a couple pieces to match outside size of tweeter and perfect round cut to go around dome fairly close noticed slight change in sound stage. Then made another to stack that's when I notice loss of sparkle. Using blue tak so I can install and remove quickly for now. Maybe there is something to cut out being rectangle or star pattern, or stepping each layer with larger cut out like a horn. Does it matter how close felt is to button of tweeter? I'm going to just try strips for a square pattern and see what happens. I agree if there is a benefit why don't speaker manufactures use this, maybe cause it's ugly, if it works I don't care.

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?
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.
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....