RoyC Posted July 28, 2012 Report Share Posted July 28, 2012 I bought half of a square meter of cheap black linen ysterday. It cost me less than 6 bucks for both speakers.I cut the fabric to dimensions and stapled it to the grills this afternoon. Then I put the badges. Here is the result:That weave is too tight, and is likely to affect high frequencies. The appropriate linen has a much lower thread count.Roy Link to comment Share on other sites More sharing options...
quebecois59 Posted July 28, 2012 Author Report Share Posted July 28, 2012 That weave is too tight, and is likely to affect high frequencies. The appropriate linen has a much lower thread count.RoyWhen you say "affect high frequencies", I supposed you can hear a big difference? How big is it? In other words, is it a theorical difference or has it been measured and documented before? Link to comment Share on other sites More sharing options...
RoyC Posted July 29, 2012 Report Share Posted July 29, 2012 When you say "affect high frequencies", I supposed you can hear a big difference? How big is it? In other words, is it a theorical difference or has it been measured and documented before?The differences are not theoretical, and are quite measurable, which is why acoustically transparent cloth should be used. Carl (Carlspeak) has posted a number of tests in this forum showing the reduction in high frequencies by various types of cloth. AR used a type of linen sold by needlepoint material suppliers today. Here is a popular source for the material: http://www.123stitch...pl?item=59-135XCarl also provides appropriate cloth for this purpose. If you like the dark cloth, there are modern polyester materials which are also acoustically transparent.Listen to your speakers with and without the grilles on. If you do not hear a difference, or the difference is not significant to your ear, don't worry about it.Roy Link to comment Share on other sites More sharing options...
quebecois59 Posted July 29, 2012 Author Report Share Posted July 29, 2012 The differences are not theoretical, and are quite measurable, which is why acoustically transparent cloth should be used. Carl (Carlspeak) has posted a number of tests in this forum showing the reduction in high frequencies by various types of cloth. AR used a type of linen sold by needlepoint material suppliers today. Here is a popular source for the material: http://www.123stitch...pl?item=59-135XCarl also provides appropriate cloth for this purpose. If you like the dark cloth, there are modern poyester materials which are also acoustically transparent.Listen to your speakers with and without the grilles on. If you do not hear a difference, or the differecne is not significant to your ear, don't worry about it.RoyThanks RoyI can hear the difference. I wouldn't have thought it could be so critical to put a fabric that is just a bit tighter... I remember the lady at the fabric store showed me another black, pure linen fabric, looser and 3 times more expensive than the one I bought. If it is a 18 string per inch, it would be fine.Oh well, I think I lost 5 bucks! Link to comment Share on other sites More sharing options...
JKent Posted August 1, 2012 Report Share Posted August 1, 2012 18 is perfect. Link to comment Share on other sites More sharing options...
quebecois59 Posted September 29, 2012 Author Report Share Posted September 29, 2012 Hey thereI've been quiet on this forum for a couple of months, because my wife had kept me busy with other urgent tasks...I just finished fixing my second speaker with new caps, and L-Pads. While typing this, I'm listening to "Animals" from Pink FLoyd, and I really like what I hear. The only remaining step is to stuff the speaker back with its wool. Of course, I'll have to change the grille material after that.For the moment, I can't hear any difference between the speaker with pots and original caps compared to the one with new caps and L-pads...would it change eventually?THanks to Kent and others who helped me a lot! Link to comment Share on other sites More sharing options...
RoyC Posted September 30, 2012 Report Share Posted September 30, 2012 For the moment, I can't hear any difference between the speaker with pots and original caps compared to the one with new caps and L-pads...would it change eventually?If the original caps you replaced were not out of spec by much, the sound difference won't be dramatic. The sound of the speaker with the new components should remain more constant than the speaker with the original components. There is no "eventual" change associated with the work you have done.There should be no difference in sound between L-pads with the added 25 ohm resistor and (operational) original pots.Roy Link to comment Share on other sites More sharing options...
quebecois59 Posted October 1, 2012 Author Report Share Posted October 1, 2012 Thank you Roy,For some reason, I was under the impression that I should add a 25 ohm resistor to the tweeter L-pad only and leave the Mid-Lpad as is (without resistor), but I may be wrong , I mean, please tell me if I am, and if so, what could be the side effects of my mistake?Also, how critical could it be for the sound if my tweeters are not perfectly sealed? The tiny electrical leads on their face look very fragile and I'm reluctant to unscrew the tweeters and move them up enough to put some sealant underneath.Francois Link to comment Share on other sites More sharing options...
RoyC Posted October 1, 2012 Report Share Posted October 1, 2012 Thank you Roy,For some reason, I was under the impression that I should add a 25 ohm resistor to the tweeter L-pad only and leave the Mid-Lpad as is (without resistor), but I may be wrong , I mean, please tell me if I am, and if so, what could be the side effects of my mistake?Also, how critical could it be for the sound if my tweeters are not perfectly sealed? The tiny electrical leads on their face look very fragile and I'm reluctant to unscrew the tweeters and move them up enough to put some sealant underneath.FrancoisFrancois,Actually, the midrange benefits more from the added resistor than the tweeter. The L-pad without the resistor allows more power to the driver, increasing output. It also lowers the crossover point a bit. The reticent AR tweeters need all the help they can get, so for that reason I usually do not use the extra resistor with the tweeter L-pad. I do, however, use the resistor with the midrange l-pad to keep the midrange response as close to original as possible. You have it reversed. It won't hurt anything, but it isn't optimal.All drivers should be sealed properly to prevent cabinet leaks. It is the woofer that is affected by any cabinet leak, whether it be from an improperly sealed tweeter or something else.Your tweeters are probably sealed well enough if you didn't remove them. Tighten the screws if they seem loose.Roy Link to comment Share on other sites More sharing options...
quebecois59 Posted October 2, 2012 Author Report Share Posted October 2, 2012 Francois,Actually, the midrange benefits more from the added resistor than the tweeter. The L-pad without the resistor allows more power to the driver, increasing output. It also lowers the crossover point a bit. The reticent AR tweeters need all the help they can get, so for that reason I usually do not use the extra resistor with the tweeter L-pad. I do, however, use the resistor with the midrange l-pad to keep the midrange response as close to original as possible. You have it reversed. It won't hurt anything, but it isn't optimal.All drivers should be sealed properly to prevent cabinet leaks. It is the woofer that is affected by any cabinet leak, whether it be from an improperly sealed tweeter or something else.Your tweeters are probably sealed well enough if you didn't remove them. Tighten the screws if they seem loose.RoyI realize now that I forgot to mention that none of my drivers were properly sealed before I remove them, the only "sealant" in place were very thin foam rings. I don't think this is what you'd call a good seal! Would it be correct to put a thin lip of sealant all around the tweeter edge without removing it? Link to comment Share on other sites More sharing options...
RoyC Posted October 2, 2012 Report Share Posted October 2, 2012 I realize now that I forgot to mention that none of my drivers were properly sealed before I remove them, the only "sealant" in place were very thin foam rings. I don't think this is what you'd call a good seal! Would it be correct to put a thin lip of sealant all around the tweeter edge without removing it?AR used foam gaskets from the early 70's on, and they worked quite well. Adding something around the drivers' edges would be helpful if you think there is a leak.If there is nothing at all under the tweeters, or any of the other drivers, you really should put gaskets under themRoy Link to comment Share on other sites More sharing options...
quebecois59 Posted October 2, 2012 Author Report Share Posted October 2, 2012 AR used foam gaskets from the early 70's on, and they worked quite well. Adding something around the drivers' edges would be helpful if you think there is a leak.If there is nothing at all under the tweeters, or any of the other drivers, you really should put gaskets under themRoyHow would I know if these foams gaskets I have under my drivers are still sealing properly or not? Is there a minimum thickness acceptable?Another question: I'm planning to put one of these speakers on a shelf in one corner of my office, how much space should I keep behind and above the speaker for better performance? My office has roughly 12 X 14 feet by 7 feet high. Link to comment Share on other sites More sharing options...
RoyC Posted October 2, 2012 Report Share Posted October 2, 2012 How would I know if these foams gaskets I have under my drivers are still sealing properly or not? Is there a minimum thickness acceptable?Another question: I'm planning to put one of these speakers on a shelf in one corner of my office, how much space should I keep behind and above the speaker for better performance? My office has roughly 12 X 14 feet by 7 feet high.Gently push the woofers in. If they don't spring right back, the seal is good enough...There is no easy answer to your shelf question. There are too many variables.Roy Link to comment Share on other sites More sharing options...
quebecois59 Posted October 2, 2012 Author Report Share Posted October 2, 2012 Gently push the woofers in. If they don't spring right back, the seal is good enough...There is no easy answer to your shelf question. There are too many variables.RoyAll right, thanks Roy.Both speakers failed the test, I got to seal them soon... Link to comment Share on other sites More sharing options...
quebecois59 Posted October 4, 2012 Author Report Share Posted October 4, 2012 I sealed all drivers, including the tweeters. I did it carefully, no problem.This said, I would say first that I'm very satisfied with the sound of these speakers. Bass response is amazing. Violins, clarinettes and saxophones sound very clear, though. I like the way they reproduce human voices, too. Link to comment Share on other sites More sharing options...
maruss Posted November 27, 2012 Report Share Posted November 27, 2012 Hey thereI knew nothing about AR speakers before yesterday evening. I gave a hand to one of my neighbour to bring all sorts of scraps to the ecocenter. I realized that he had a pair of old speakers in his trailer. They were quite dirty and didn't look in very good shape at first. You threw lots of garbage in the bins at the ecocenter and then it was the speakers turn. I first removed the damaged grills (and threw them in the bin) to have a look at the speakers and even if I'm not an expert I thought that they might be of good quality.I asked my neighbour if I could keep them to check for infos. Later in the evening I surfed on the web and discovered that AR-2ax speakers are pretty good ones! So I hooked them on my system one at a time. One of them was working well, it delivered a better sound than my usual speakers even if the woofer foam surround is toasted! The other AR speaker didn't perform very well, it sounded like the MID et HI speakers were not working at all, and the woofer surround is toasted too.So I'm a bit ambivalent if I should keep and restore them or not. I went back to the ecocenter this morning to get the grills back even if they look terrible, so I'm ready to get involved in the process!I already restored my JVC Zero 3 surrounds 2 years ago so I'm not a total newby in this kind of work, but I do need some good basic infos and advices to achieve the AR-2ax restoration. I haven't touched anything for the moment except that I gently removed the gyproc dust off of the tweeters and Mid-ranges with a toothbrush.English is not my first language so please take it in consideration.I read a couple of threads and realized that I don't know what "drivers", "pots" and "caps" refer to.Thanks in advance.FrancoisHi there, can you offer me any advice on re-foaming the JVC Zero 3s? I have acquired a pair and they badly need doing.Any help here appreciated.Mark. Link to comment Share on other sites More sharing options...
JKent Posted November 27, 2012 Report Share Posted November 27, 2012 Hi there, can you offer me any advice on re-foaming the JVC Zero 3s? I have acquired a pair and they badly need doing.Any help here appreciated.Mark.Welcome MarkContact this ebay seller. He will sell you a very complete DIY kit with the correct foams for your speakers.Kenthttp://www.ebay.com/itm/JBL-122-128-other-12-reFoam-Kit-speaker-foam-/330355434215?pt=US_Amplifier_Parts_Components&hash=item4ceab7e2e7 Link to comment Share on other sites More sharing options...
quebecois59 Posted November 28, 2012 Author Report Share Posted November 28, 2012 Welcome MarkContact this ebay seller. He will sell you a very complete DIY kit with the correct foams for your speakers.Kenthttp://www.ebay.com/...=item4ceab7e2e7Hey MarkI refoamed my JVC Zero 3s at least ten years ago, I wouldn't have been able to remember what product I used exactly. But Kent gave you a very good link.THese JVCs sound pretty good. They deserve some work.Francois Link to comment Share on other sites More sharing options...
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