Guest jclavin Posted August 23, 2006 Report Share Posted August 23, 2006 I am finishing up a restoration of a pair of AR-3a's (replaced caps with solens, refoamed woofers, and replaced pots with rheostats). I am the original owner of these units, purchased 1972. When I removed the fiberglass, I found that it had settled to the lower third of the cabinet and primarily occupied the space behind the woofer. Some of it was rather tightly stuffed around the crossover components and their wiring as though it were possibly preventing vibrations.Any guidance regarding the best way to restuff the fiberglass? Also, on my units the fiberglass was isolated from the rear of the woofer by a sheet of brown tissue paper.Thanks in advance, John Link to comment Share on other sites More sharing options...
Carlspeak Posted August 24, 2006 Report Share Posted August 24, 2006 >I am finishing up a restoration of a pair of AR-3a's>(replaced caps with solens, refoamed woofers, and replaced>pots with rheostats). I am the original owner of these units,>purchased 1972. >>When I removed the fiberglass, I found that it had settled to>the lower third of the cabinet and primarily occupied the>space behind the woofer. Some of it was rather tightly stuffed>around the crossover components and their wiring as though it>were possibly preventing vibrations.>>Any guidance regarding the best way to restuff the fiberglass?>Also, on my units the fiberglass was isolated from the rear of>the woofer by a sheet of brown tissue paper.>>Thanks in advance, >JohnI wouldn't sweat it John. I find it hard to imagine folks on the AR production line packing glass in each box exactly the same way. Who knows how yours was stuffed exactly and what localized changes in glass density occured over time and handling. Suggest you indeed put it all back in and distribute it as evenly as you can throughout the inside of the box.Remember, it's all about the musicCarlCarl's Custom Loudspeakers Link to comment Share on other sites More sharing options...
JKent Posted August 25, 2006 Report Share Posted August 25, 2006 >Also, on my units the fiberglass was isolated from the rear of>the woofer by a sheet of brown tissue paper.John O'Hanlon filled me in regarding that paper:the "flimsy paper" --made by Kimberly Clark, is a paper that stops most of the fine fiberglass dust from making it through to the woofer.Re-install it just as it was when you opened the cabinets. Everything they did in those cabinets was for a specific purpose! Well engineered, fussy detail.(hope you don't mind me quoting you here John).My question is; anyone have a suitable replacement suggestion for the Kimberly Clark stuff? Or is it still available? Link to comment Share on other sites More sharing options...
johnieo Posted August 25, 2006 Report Share Posted August 25, 2006 >Any guidance regarding the best way to restuff the fiberglass?Depending on the history of an individual cabinet, the fiberglass may or may not have deteriorated. Maybe a little, maybe a lot. For example, settling could have (but not necessarily have) been the result of the fiberglass being broken by long term vibration into smaller pieces. Thus some of it might shift toward the cabinet base.Twenty ounces of new yellow fiberglass (sans paper backing!) is the correct replacement weight. Find a small roll of two-inch-thick material in the hardware store and cut it into 4-to-6 inch thick squares. This is a good time of year to do it, as you can work outside. Work upwind, wear gloves to keep the itchy stuff out of your skin, and fill reasonably uniformly throughout the cabinet. Yes, stuffing in and around components will prevent vibration, as will securing capacitors and wires to surfaces.After playing around with some absorbtion calculations in fiberglass, I have a suspicion that the speaker response in the upper woofer region might depend on the stuffing density near the woofer's backside--but no one has ever done any measurements to show that or has any information on how much these beasties have changed with (ab)use over thirty-five years! Link to comment Share on other sites More sharing options...
Carlspeak Posted August 25, 2006 Report Share Posted August 25, 2006 >>Also, on my units the fiberglass was isolated from the>rear of>>the woofer by a sheet of brown tissue paper.>>John O'Hanlon filled me in regarding that paper:>>the "flimsy paper" --made by Kimberly Clark, is a>paper that stops most of the fine fiberglass dust from making>it through to the woofer.>Re-install it just as it was when you opened the cabinets.>Everything they did in those cabinets was for a specific>purpose! Well engineered, fussy detail.>(hope you don't mind me quoting you here John).>>My question is; anyone have a suitable replacement suggestion>for the Kimberly Clark stuff? Or is it still available?I have two suggestions. Try searching packaging supplies. That brown paper is like some stuff I've seen used just for that purpose. It may come in multiple layers to bulk it up and provide a cushioning effect. Peel it down to 1-2 layers should be suitable. The other suggestion is more easily acquired. In fact, you may already have it in your home. This may sound rediculous, but toilet paper is very much like the stuff made by KC and used in AR speakers. After all, KC is/was one of the country's largest producers of toilet paper. Taping a half dozen or so sheets of toilet tissue together side-by-side should do the trick. Single layer Scott toilet tissue is also a good bet or, Charmin which is more bulkier - like the old KC stuff.Remember, it's all about the musicCarlCarl's Custom Loudspeakers Link to comment Share on other sites More sharing options...
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