Replacing diffraction foam on an AR11 200003 woofer?

[Johnny_Law]

As is commonplace, I recently replaced the foam surrounds on my AR11B's 200003 woofers. The foam replacement went well.

However, in order to get to the screws, I had to remove the layer of felt-like material that was stuck to the woofer frame to act as a diffraction ring. Now I'm wondering what to use to make a new one.

Here's the pic before the re-foam. You can see the black foam diffraction layer on the outer woofer frame outside of the cardboard ring dlued atop the outer surround foam.

And here's a pic after the re-foam ... nice new foam but obviously no more diffraction ring (you can see the silver woofer frame exposed).

Who has made a replacement that works well? Any suggestions?

Thanks!
Ryan

 

[sreten]

Hi,

Its purpose was cosmetic . It has next to no effect on diffraction.

rgds, sreten.

 

[michiganpat]

I made my own for my 58S's...first pair was from some 1/8" thick 11x17 sheets of black craft foam from JoAnn's fabric...didn't care for the look, and I found some more correct looking foam here at work that was headed for the dumpster that I think came from McMaster Carr...

 

[GD70]

Pat made a pair for me for my AR12's and they look great!
I also had to make new decorative gaskets for the mids and tweeters, the original foam was crumbling.
Here's a few pics of the foam ring from Pat.

 

[Johnny_Law]

Thanks all - I guess even though it's mostly cosmetic, I do want to keep it original looking, so I'll hunt for some material and then see if I can trace an outline and make a circular cut somehow.

 

[michiganpat]

the foam for Glenn's 10's were left over from mine when I made them for my 12's....the left over from his 10's, I plan on making 8"ers for my ADD series AR18's.....

 

[michiganpat]

here's how I made them:

http://www.audiokarma.org/forums/in...-rings-ar9-10-11-58s-etc.708083/#post-9506105

if I had to do it over again, make the base big enough to fit the entire 12" woofer circle. on the 2nd set I made, I hand trimmed the flats to the actual basket. came out much better.

on my cutter arm, I just drilled some additional holes to get the proper radii for the ID and OD for the 10's and 8's....

for the screw cutouts on glen's (and on my 2nd set), I used a hollow gasket punch similar to these:

http://www.harborfreight.com/9-piece-hollow-punch-set-3838.html

that I have. I had the woofer installed, and the new ring on, being held by friction, and then felt for the screw head, centered the punch over it, and popped out the circle....on Glens' I just used a spare 10" 4 hole woofer to figure out placement, punched them out, and then cut out the open top of the U with an exacto knife.