Hi, I'm in the process of restoring a pair of Magnat 8P Acrylic and when I took the mid range speaker apart I noticed there is a foam plug inside it which is falling apart as soon as I touch it. I want to replace it but what material is this? Can I use a piece of a dish washing sponge cut to the same dimensions or is this some special rocket science foam? I didnt find any info on the internet watsoever.
Thank you 🙂
Arne
Thank you 🙂
Arne
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Greets!
Normally open cell foam with a ppi to suit the eigenmodes it's there to damp. FYI/FWIW/YMMV, Dr.Geddes' horn foam plug is 30 ppi = fish tank filter IIRC, so at least an inexpensive way to get a frame of reference if your sponge is too dense.
Normally open cell foam with a ppi to suit the eigenmodes it's there to damp. FYI/FWIW/YMMV, Dr.Geddes' horn foam plug is 30 ppi = fish tank filter IIRC, so at least an inexpensive way to get a frame of reference if your sponge is too dense.
I've seen everything from open cell urethane foam to reticulated foam and even used melanin sponge (magic eraser) foam. I like the melamine stuff because it doesn't migrate as much under vibration under the dust cap. It also works well in tweeters and dome mids.
This stuff is amazing for tweeters and dome mids. It does change the low frequency characteristics of a tweeter sometimes in unexpected ways, but usually dampens the primary Fs peak more than urethane foam but not as good as sheep's wool. For most higher end tweeters the sheep's wool is still the preferred dampening.
Thanks a lot for the solution to my problem! Actually I have both at hand but as the tweeter as well as the mid range are cooled with ferro fluid I think the magic eraser will be my choice so it wont end up being a mess inside.
Thanks again and have a good weekend!
Arne
Thanks again and have a good weekend!
Arne