Guest cy Posted October 23, 2004 Report Share Posted October 23, 2004 Hello fellows,I recently acquired a fairly decent pair of AR 91's..aside from the usual foam surround deterioration, the foam around the midrange and highrange drivers have also deteriorated. 1.Does anybody know the sonic importance of the foam around the drivers? 2.what would be a comparable replacement? 2.where could one get this replacement?Thank you all in advance. Warm regards,Cyrus Link to comment Share on other sites More sharing options...
ar_pro Posted October 24, 2004 Report Share Posted October 24, 2004 Hi, Cyrus -The woofer foam is critical to the air-seal, and should absolutely be replaced. The upper drivers of the AR-91 don't use a foam surround, and aren't subject to the same type of deterioration. For expert re-foaming of the woofer, many people recommend Millersound: (215) 412-7700 Link to comment Share on other sites More sharing options...
Guest cy Posted October 25, 2004 Report Share Posted October 25, 2004 thank you ar_pro,i was referring to the deteriorating foam (insert) on the "acoustic blanket" that is on the mid and highrange drivers,much like the next question (of the AR 9)...i have temporarily substituted felt fabric for now. any more advice would be greatly appreciated. thanks,cyrus Link to comment Share on other sites More sharing options...
Guest Barrydor Posted October 25, 2004 Report Share Posted October 25, 2004 >thank you ar_pro,>i was referring to the deteriorating foam (insert) on the>"acoustic blanket" that is on the mid and highrange>drivers,much like the next question (of the AR 9)...i have>temporarily substituted felt fabric for now. any more advice>would be greatly appreciated. thanks,>cyrusThe foam inserts were not included with earlier versions of the AR9, including my own pair, circa 1978. Apparently, many pairs of AR9s came from the factory without the inserts. From the time frame involved, it is my guess that the inserts came about at the time the AR90 and AR91 were released and were included with the AR9 from that point forwardAccording to a past post from someone who once worked at AR (it was Ken Kantor, I believe), AR had some issues with the inserts. Apparently, some materials turned out to be acoustically reflective rather than absorbent and did more harm than good. AR had to carefully choose the material used for the insertsThere were some past posts from someone who claimed to be having the inserts and the decorative woofer rings made up, but I have not heard anything about this in awhile. I do not know what material the new parts are made of or whether they are the same material as the original onesI think it is debatable whether the inserts make a noticeable sonic difference. I cut my own fillers from fairly thick pieces of cotton-felt material, which I doubled up. I cut them slightly oversize so they stay in place on their own without using the Velcro pads the factory used. I believe the imaging was slightly better with the pads, but the difference was very subtleBarry Link to comment Share on other sites More sharing options...
Guest cober Posted October 25, 2004 Report Share Posted October 25, 2004 Thanks Barry, I posted the AR9 question.I still am curious why AR elected to use a foam material on the AR9 insert instead of the acoustic blanket material.I can understand why AR would use an insert to allow speaker assembly and service. But some supplier back then was die cutting the 1/2" acoustic blankets and throwing away the cutouts that could have served as inserts. ?? Link to comment Share on other sites More sharing options...
Guest Barrydor Posted October 25, 2004 Report Share Posted October 25, 2004 >Thanks Barry, I posted the AR9 question.>>I still am curious why AR elected to use a foam material on>the AR9 insert instead of the acoustic blanket material.>>I can understand why AR would use an insert to allow speaker>assembly and service. But some supplier back then was die>cutting the 1/2" acoustic blankets and throwing away the>cutouts that could have served as inserts. ??You make a very good pointAnd I will never understand why the upper midrange cutout is square instead of round - to me, it looks sort of hokey with or without the insertsBarry Link to comment Share on other sites More sharing options...
Guest cober Posted October 26, 2004 Report Share Posted October 26, 2004 Yes, the square shape for the high mid cut-out in the acoustic blanket on the AR9 is wierd.On a whim, I held the original AR foam insert material, 2 layers thick, directly blocking the tweeter. With my face immediately in front of the tweeter I could not detect any tonal change imparted by material reflection or absorption, so this foam appears to be acoustically transparent. I think now these inserts were merely a cosmetic feature. The running change add in 1978 AR9 production supports this also. Link to comment Share on other sites More sharing options...
soundminded Posted October 27, 2004 Report Share Posted October 27, 2004 Whew! Thanks Barry. When I read the original posting, I looked at mine and wondered if something important was missing. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.