ninohernes Posted December 12, 2003 Report Share Posted December 12, 2003 What do you guys typically use to seal the drivers into the cabinets, if the original putty has hardened? I have been working on a pair of AR-4x's and the putty that seals the woofer is very brittle, pretty much un-usable. Link to comment Share on other sites More sharing options...
soundminded Posted December 12, 2003 Report Share Posted December 12, 2003 This brings up an interesting question. I recall a photo widely published in AR advertising showing an engineer or technician testing the cabint of an AR3 or AR3a for tighness of air seal. But there was a posting here recently that said that the cabinets shouldn't be too tight because that would create a problem due to changes in exterior barometric pressure. So just how air tight should an AR speaker cabinet be and how do you get it just right? I always thought it needed to be absolutely sealed. And are the paper woofer cones porous either initially or become that way over time? Is the paper chemically treated? Link to comment Share on other sites More sharing options...
tysontom Posted December 12, 2003 Report Share Posted December 12, 2003 >This brings up an interesting question. I recall a photo>widely published in AR advertising showing an engineer or>technician testing the cabint of an AR3 or AR3a for tighness>of air seal. But there was a posting here recently that said>that the cabinets shouldn't be too tight because that would>create a problem due to changes in exterior barometric>pressure. So just how air tight should an AR speaker cabinet>be and how do you get it just right? I always thought it>needed to be absolutely sealed. And are the paper woofer>cones porous either initially or become that way over time? >Is the paper chemically treated? Soundminded,If the cabinet of an acoustic-suspension loudspeaker is completely air-tight, or hermitically sealed, the speaker cone will act like an aneroid barometer. With changes in outside air pressure, the cone would move away from the "center" position. What is needed, however, is an "acoustical" seal such that the speaker is sealed down to the lowest frequency in which that speaker will be used.Acoustical seals do require that there are no obvious air leaks around the gaskets, etc., but also take into account that some tiny amount of air will leak through the cabinet at certain places, such as the level-control shafts or porous dust caps and so forth. This tiny leak is not enough to upset the acoustic-suspension restoring force. A rule of thumb is to gently push in the cone with your fingers (ringed around the dust cap), hold for a second or two, and quickly release the cone. If the cone immediately pops back out to the resting position, there is an unwanted air leak. If the cone moves back out fairly slowly, as if moving through a viscous fluid, you are probably fine. You can actually time the movement of the cone at one-half cycle vs. the lowest frequency, and so forth, but just eye-balling the slow return is generally a good guide to the quality of the seal.--Tom Tyson Link to comment Share on other sites More sharing options...
ninohernes Posted December 12, 2003 Author Report Share Posted December 12, 2003 On my AR-4's I had to remove the woofer to repair the crossovers. The putty between the woofer frame and the wood of the cabinent had become hard, I could not re use it to restore the seal. What I am asking is, what is a good replacement for this putty. Link to comment Share on other sites More sharing options...
tysontom Posted December 12, 2003 Report Share Posted December 12, 2003 >On my AR-4's I had to remove the woofer to repair the>crossovers. The putty between the woofer frame and the wood of>the cabinent had become hard, I could not re use it to restore>the seal. What I am asking is, what is a good replacement for>this putty.The putty that was used was Mortite. Mortite works extremely well, and it does not harden or dry out for probably twenty or thirty years -- of course what you are now beginning to witness.http://www.energyfederation.org/consumer/d...cPath/21_392_71If you choose not to use Mortite, you can use a standard foam gasket, and you might have to go through someone like AB Tech Services. The 8-inch woofer does have a pretty standard-size frame, so a gasket shouldn't be hard to locate. You could, of course, use something like window putty or a similar material, but it is messy. Don't use DAP, silicon rubber or anything like that because it will make it impossible to remove the woofer later on.--Tom Tyson Link to comment Share on other sites More sharing options...
Guest dogmeninreno Posted December 12, 2003 Report Share Posted December 12, 2003 >What do you guys typically use to seal the drivers into the>cabinets, if the original putty has hardened? I have been>working on a pair of AR-4x's and the putty that seals the>woofer is very brittle, pretty much un-usable.I have used plumbers putty with good results (available at Home Depot). It fills voids and is easy to handle. Just roll it like you would when setting a sink drain. Set the driver and trim the excess.Dale in Reno..... Link to comment Share on other sites More sharing options...
ninohernes Posted December 12, 2003 Author Report Share Posted December 12, 2003 Ok, thanks for the link! I bought some, I will apply it when it arrives. Also, on the topic of sealing. One of my AR-4x woofers has wide masking tape wrapped around the magnet, the other one does not, it only has screens on the sides of the magnet. Should I apply tape on the second one? or remove the tape from the first one? Link to comment Share on other sites More sharing options...
soundminded Posted December 12, 2003 Report Share Posted December 12, 2003 I seal my speakers with spare Morton Thiokol O-rings. I'm just careful not to listen to them when the temperature inside drops below freezing. Link to comment Share on other sites More sharing options...
tysontom Posted December 12, 2003 Report Share Posted December 12, 2003 >I seal my speakers with spare Morton Thiokol O-rings. I'm>just careful not to listen to them when the temperature inside>drops below freezing.Yes, it is recommended to allow the Thiokol/AR O-rings "settle" down -- warm up -- before acoustical liftoff. Link to comment Share on other sites More sharing options...
tysontom Posted December 12, 2003 Report Share Posted December 12, 2003 >Ok, thanks for the link! I bought some, I will apply it when>it arrives. Also, on the topic of sealing. One of my AR-4x>woofers has wide masking tape wrapped around the magnet, the>other one does not, it only has screens on the sides of the>magnet. Should I apply tape on the second one? or remove the>tape from the first one?Those are just variations on the same theme. I would not worry about it either way: leave the tape on -- and don't remove the tape or the screens. They are there simply to keep fiberglass and other foreign matter out of the voice coil/gap area. Those are superb woofers, incidentally, and a way to help restore the impregnated-cloth surround ("impregnated" with a butyl-rubber substance, by the way) is to take a paint brush and put two or three light coats of Armoral (the tire stuff) protectant on the surround. This will soften the surround and restore its performance somewhat. This works well for all of the cloth-surround AR speakers.--Tom Tyson Link to comment Share on other sites More sharing options...
Guest rbl Posted December 22, 2003 Report Share Posted December 22, 2003 >Those are superb woofers, incidentally, and a way to>help restore the impregnated-cloth surround ("impregnated">with a butyl-rubber substance, by the way) is to take a paint>brush and put two or three light coats of Armoral (the tire>stuff) protectant on the surround. This will soften the>surround and restore its performance somewhat. This works>well for all of the cloth-surround AR speakers.Well, I've re-foamed a pair of Ambients (Orange County Speaker re-dege kit -- great directions and results) and now I want to take a look at my AR-4xs.At least one sounds as though the surround is gone around the woofer. Do you recommend trying to restore the cloth or replacing with a new (foam) edge kit?And ... just how in heck to you get the grill off the 4x without smashing the frame, chipping the speaker veneer or tearing the cloth??-RBL Link to comment Share on other sites More sharing options...
ninohernes Posted December 22, 2003 Author Report Share Posted December 22, 2003 >And ... just how in heck to you get the grill off the 4x>without smashing the frame, chipping the speaker veneer or>tearing the cloth??>>-RBLSlowly and carefully. It took a long time to get mine off. Under each corner of the grill frame, there is a spot of glue. Free these spots first. I used a flat screwdriver and pryed very gently until it popped free. There is also a spot of glue half way down the grill where the frame meets the support that runs across the center. With carefull prying, the grills pop right off. About the surrounds, I would replace them, only if the original ones are torn, or creased. Once your 4x's are up and running, they are a great sounding loudspeker. They sound much better than anything of the same size made today. Just go easy on the power, about 60 watts (RMS) is about it. Mabye 100 watts if its really clean. The lowish power handling is really the only issue with this particular model. Link to comment Share on other sites More sharing options...
tysontom Posted December 23, 2003 Report Share Posted December 23, 2003 >>Well, I've re-foamed a pair of Ambients (Orange County Speaker>re-dege kit -- great directions and results) and now I want to>take a look at my AR-4xs.>>At least one sounds as though the surround is gone around the>woofer. Do you recommend trying to restore the cloth or>replacing with a new (foam) edge kit?>>And ... just how in heck to you get the grill off the 4x>without smashing the frame, chipping the speaker veneer or>tearing the cloth??>>-RBLRBL,The AR-4x is a great speaker to restore, and it is truly one of the finest small speakers ever made. There's nothing "exciting" about the sound, but it is clean, smooth and accurate all the way.Joe is right about carefully going around the edge of the grill frame and gently prying a little at a time until it frees up. The glue that AR used is simply an industrial-grade USM hot glue, and it never completely hardens, therefore allowing a gentle tug to pry it loose. Be careful not to mar the cabinet molding in the process. I have found that a wide putty knife is usually best in that it has a wider surface against which to pry. The molding on nearly all of the AR-4x's was wood rather than masonite, so you must be careful not to force it too hard. Once it starts to come loose, you can work it around the edge until it finally pops loose.It's actually quite rare to find a really bad cloth surround unless the speaker was subjected to harsh environmental conditions (heat or mosture) that have caused it to deteriorate badly or dry out or whatever. I have seen very few that were really in need of a new surround, and I quite frankly like the cloth surround better than the foam on the little woofer, but if the surround has dried out badly, it will make noise and it may indeed leak air. If the surround still is intact, but has dried out, you can also apply a coat of butyl-rubber compound on the surrounds to bring them back to their original condition. Alternatively, of course, you can have the surround replaced with a foam surround. You should do both woofers the same.One thing is for sure: you should go in and clean/refurbish the level control while the woofer is out of the cabinet. There is a definite method-to-that-madness, so we can help you on this forum if you decide to do that also.--Tom Tyson Link to comment Share on other sites More sharing options...
tysontom Posted December 23, 2003 Report Share Posted December 23, 2003 I meant to also mention again the use of Armor All to put on the cloth surrounds. It's the automotive stuff (a polymer of some sort) that is actually absorbed into rubber and vinyl, and tends to soften up that surface along with the shine for tires, of course. I have used it for years on AR-3's and AR-2's and other cloth-surround speakers, and it works quite well if you use several coats spread out over a few days. The surround must be in fairly decent condition to start with, though, or the Armor All will not help matters.--Tom Tyson Link to comment Share on other sites More sharing options...
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