PPI of the foam in AR9LS/LSI bass chamber

[cd0nc]

Does anybody know the PPI of the original foam in AR9LS/LSI bass chamber?

Mine turned to mush before getting a measurement. I'm thinking of going with 30PPI but thought to check here in case anybody knows the actual value.

[AR55]

I have never found an answer to that question.

I replaced the foam in my 9Lsi's base chamber about 10 years ago.  The porosity of the foam that I used is definitely not fine - probably close to 30 PPI.  I feel that my speakers' base response is deep and clean, so I think that I guessed correctly.

If you are interested, Vintage-AR (eBay) sells a foam chamber precut kit for a rather pricey $100.  I don't know, however, if their foam is any closer to the original AR spec then what I used.

[Scoup]

Mine was also too soft to get any useable info from.  I got my foam cut at a local foam shop.  For $60 I got 3 different weights.  They are a tight fit so I didn’t glue them in.  I’ve been testing the 3 different density sets and I can hear no noticeable difference.

[Stimpy]

Vintage AR, via ebay, sells a pre-cut foam kit.

https://www.ebay.com/itm/ACOUSTIC-RESEARCH-AR-9LS-AR-9LSI-BASS-CHAMBER-FOAM-KIT/162368817302?hash=item25cdef8896:g:b1YAAMXQjq5Q9QnG

 

DIY types often buy Sonic Barrier foam from Parts Express, and cut their own kit.

https://www.parts-express.com/sonic-barrier-1-acoustic-sound-damping-foam-with-psa-18-x-24--260-525

There's 3 different thicknesses to choose from.  Use what's appropriate.