Guest Posted September 30, 2002 Report Share Posted September 30, 2002 I'm in the process of refurbishing a pair of 3a's. I noticed the insulation inside has started to shred and loosen up. Is it worth replacing the insulation and if so, how critical is the quantity of the material. Link to comment Share on other sites More sharing options...
Guest dogmeninreno Posted September 30, 2002 Report Share Posted September 30, 2002 My experience is that you should use a polyester material instead of the fiberglass. They seem to have no noticable differences to me. The best people to ask are Nigel or Tom Tyson among others on this forum. Dale in Reno..... Link to comment Share on other sites More sharing options...
Guest Posted September 30, 2002 Report Share Posted September 30, 2002 There is a product I think it is called Acoustistuff. I used polyester pillow stuffing from a local craft store for stuffing a transmission line sub I built. Seems to have worked fine. Link to comment Share on other sites More sharing options...
tysontom Posted September 30, 2002 Report Share Posted September 30, 2002 >I'm in the process of refurbishing a pair of 3a's. I noticed >the insulation inside has started to shred and loosen up. Is >it worth replacing the insulation and if so, how critical is >the quantity of the material. The original fiberglass insulation -- which, incidentally, works fine -- was intentionally shredded or sliced into pieces and put in the cabinet loosely packed. Pieces of the insulation were tucked in the wiring on the crossover to keep things from vibrating, and the rest was placed inside the cabinet appropriately. The important thing to remember is this: in acoustic-suspension loudspeakers, damping is afforded by three means, (1) electrical, (2) mechanical and (3) acoustical. The fiberglass in the cabinet is an integral part of the damping of acoustic-suspension speakers, and a *specific* amount is intentionally put in the cabinet. Too little fiberglass increases the "Q" of the speaker and causes underdamping (boominess) in the area of resonance; too much fiberglass has the opposite effect of overdamping (dryness) the speaker and lowering the "Q."The best thing to do is to take out the original fiberglass and allow it to be completely dry if it has absorbed any mosture over the years. Keep the specific amount that was removed so that it can be re-installed in the speaker once restoration is complete. Replace that same quantity of fiberglass the same way it was removed. Also, be sure to put a layer of Kimberly-Clark crepe-type paper just below the woofer, tucked around the sides of the cabinet, with the woofer leads going through a hole in that paper. This layer of tissue-like paper will keep the fiberglass from interfering with the woofer cone, while allowing air to freely move. In some cases, AR woofers had a screen mesh covering the openings, and the paper is not necessary. --Tom Tyson Link to comment Share on other sites More sharing options...
Guest Posted September 30, 2002 Report Share Posted September 30, 2002 Thanks Tom. I'm glad I waited for your response and didn't take the advise of a local speaker repair shop. They advised to just stuff it full of fiberglass insulation after removing the original. The only thing I'll replace is the fabric you spoke of which has come apart over the years. I'll post the results of the restoration after the woofers are refoamed, the dead mid replaced, grill cloth replaced and the level controls are replaced. The cabinets, after a little elbow grease, are looking great. My thanks also to Dale (dogmeninreno) for his advise and assistance. Link to comment Share on other sites More sharing options...
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