ironlake Posted March 20, 2012 Report Share Posted March 20, 2012 Is there any easy way to test if the cloth surrounds are leaking air while in the cabinet??????thanks for any answere. Link to comment Share on other sites More sharing options...
JKent Posted March 20, 2012 Report Share Posted March 20, 2012 Sure--just push the woofer cone inward (place your fingers like a tripod around the dustcap). If it comes right back you have a leak. It should take a sec or 2.Kent Link to comment Share on other sites More sharing options...
danajohnhill Posted March 21, 2012 Report Share Posted March 21, 2012 And don't forget that if you have the cloth surrounds, you might also have the cloth dust cap which could be leaking air, as well. Link to comment Share on other sites More sharing options...
rjr513 Posted March 21, 2012 Report Share Posted March 21, 2012 I use a 30 hz signal from a test cd in which I made then playback, I use a stethoscope,pull the scope part away from the tubing then playback your 30 hz tone while running the tube around the drivers if any air leak detected you will hear a whoosing sound in the ears Link to comment Share on other sites More sharing options...
ironlake Posted March 21, 2012 Author Report Share Posted March 21, 2012 where can you get a stethoscope??????? Link to comment Share on other sites More sharing options...
rjr513 Posted March 21, 2012 Report Share Posted March 21, 2012 most any home health care business or http://www.walgreens...Ntt=stethescope Link to comment Share on other sites More sharing options...
JKent Posted March 21, 2012 Report Share Posted March 21, 2012 bumost any home health care business or http://www.walgreens...Ntt=stethescope ....but do you really want to trust a medical supplier that calls it a "stethescope"?? Link to comment Share on other sites More sharing options...
ra.ra Posted March 31, 2012 Report Share Posted March 31, 2012 JKent's recommended tripod-finger push test seems to be the most prescribed method, and although I generally understand this concept for a sealed box, my experience with this test has rarely determined such black or white results. There appears to me to be shades of gray as well, but perhaps I have failed to interpret the rebounding cone accurately. On all of my 8" cloth surround woofers - - 40 years old and never re-doped - - there is not really an immediate return, but there is also not the slow and gradual delayed return that I imagine represents a good seal. They usually seem somewhere in between these two imprecise descriptions.Because I am currently restoring (caps, pots, the usual) several pairs of my speakers, I'd like to be able to make improvements in all areas, including the low frequency performance. I am inclined to believe that these woofers could possibly benefit from a light-handed application of goop to the fabric surrounds, but I have been holding off until I develop confidence in the proper product to use which would ensure their remaining pliant. I have read on another very recent thread (with same title: cloth surrounds) that Roy's secret recipe material now resides with vintage-AR, so I will probably start there.Another note on this thread describes possible leakage thru the dust caps - - I don't think I have ever seen this discussed, nor have I ever heard of anyone doping up their dust caps to correct this situation. Link to comment Share on other sites More sharing options...
JKent Posted March 31, 2012 Report Share Posted March 31, 2012 SOME caps should be doped; specifically the KLH (per KLH Service Bulletin in our Library) but others, as I understand it, are designed to breathe and provide some ventilation/heat dissipation.Kent Link to comment Share on other sites More sharing options...
RoyC Posted April 1, 2012 Report Share Posted April 1, 2012 JKent's recommended tripod-finger push test seems to be the most prescribed method, and although I generally understand this concept for a sealed box, my experience with this test has rarely determined such black or white results. There appears to me to be shades of gray as well, but perhaps I have failed to interpret the rebounding cone accurately. On all of my 8" cloth surround woofers - - 40 years old and never re-doped - - there is not really an immediate return, but there is also not the slow and gradual delayed return that I imagine represents a good seal. They usually seem somewhere in between these two imprecise descriptions.Because I am currently restoring (caps, pots, the usual) several pairs of my speakers, I'd like to be able to make improvements in all areas, including the low frequency performance. I am inclined to believe that these woofers could possibly benefit from a light-handed application of goop to the fabric surrounds, but I have been holding off until I develop confidence in the proper product to use which would ensure their remaining pliant. I have read on another very recent thread (with same title: cloth surrounds) that Roy's secret recipe material now resides with vintage-AR, so I will probably start there.Another note on this thread describes possible leakage thru the dust caps - - I don't think I have ever seen this discussed, nor have I ever heard of anyone doping up their dust caps to correct this situation.ra.ra,I still have some sealant for forum members. Send me a PM....If the speakers are still sealed enough to provide any kind of delayed woofer return, re-treatment is not critcal. In any case, the application of my stuff won't hurt anything.Dust caps seldom need re-treatment. If for any reason a dust cap is treated, it need not be with my sealant. Diluted glue of various types should serve the purpose.Maintaining compliance is not an issue for dust caps like it is for surrounds.Roy Link to comment Share on other sites More sharing options...
ironlake Posted April 2, 2012 Author Report Share Posted April 2, 2012 I used simply speakers goup for surrounds and put it on as super thin as I could on my ar 4x. I ran a bead as super thin as I could around the top center of the surround and then with the brush supplied I keep on brushing all around until everywhere cloth had a super thin coat of it. It dried over night and is still as flexable as it was without but when pushing down with the 3 fingers I do get a slight smooth return instead of the fast pop back I had. speaker sounds great with great bass for such a small speaker A side note here the speaker surrounds turned black with the goup. The orange tint is gone..My kid is now getting a pair for the rear seat of his car and connected to the crapy speakers (which are disconected)he had in the rear seat,. I let him try miy 4xs and wow does that give a sound improvement in the small car. Someone has a pair fully restored on ebay he is going after. Link to comment Share on other sites More sharing options...
RoyC Posted April 2, 2012 Report Share Posted April 2, 2012 I used simply speakers goup for surrounds and put it on as super thin as I cold on my ar 4x. I ran a bead as super thin as I could around the top center of the surround and then with the brush supplied I keep on brushing all around until everywhere cloth had a super thin coat of it. It dried over night and is still as flexable as it was without but when pushing down with the 3 fingers I do get a slight smooth return instead of the fast pop back I had. .Is the material you applied called "Foamguard"? If so, it is a white glue-like PVA based material. It will stiffen your surrounds...I measured an increase in fs of over 10hz with this stuff. It was one of the products that prompted us to look for something more like the original sealant.Roy Link to comment Share on other sites More sharing options...
ironlake Posted April 2, 2012 Author Report Share Posted April 2, 2012 Yes it is, but I did not notice any stiffing effect from, but if it did so be it. I can;t hear any loss of bass on them though. It was put on so very thin I can;t imagine it doing much more that sealing the cloth. Link to comment Share on other sites More sharing options...
Rob dalton Posted July 16, 2012 Report Share Posted July 16, 2012 Has anyone tried to check the resonant frequency of their woofers. For example the Ar3as I believe have a free air resonance of around 20 and a system (in cabinet) resonance of around 42HZ. This might be a tool in determining how well the cabinet/speaker is sealed, with lower in cabinet readings perhaps indicating a leak. However, the first time I tried this, i put a 30 ohm power resistor in series with the amplifier thinking i would see a notable change in current at resonance. I only have a simple B&K switch selectable tone generator so couldn't do a continuous sweep, but i didn't see much variation in current. Link to comment Share on other sites More sharing options...
RoyC Posted July 17, 2012 Report Share Posted July 17, 2012 Has anyone tried to check the resonant frequency of their woofers. .Yes...in and out of the cabinet (fc and fs, respectively).We did exhaustive measurements of the 3a when we were writing the restoration guide. I have also done many measurements of AR and KLH specimens (treated and untreated surrounds) over the past 4 years in an effort to keep folks from compromising their acoustic suspension woofer surrounds in the name of "sealing" them. Some materials, like the product mentioned above, was measured to increase fs by 10+ hz. Some audio forums are full of very bad advice in this matter.Roy Link to comment Share on other sites More sharing options...
lakecat Posted July 19, 2012 Report Share Posted July 19, 2012 I am one of those who is using Roy's sealant for my A2. I put the first coat on yesterday and after reading this thread, I went out to the workroom to see how it is curing. Much to my surprise when I did the three finger push in test, it is returning much slower than it was originally. I still have a second coat to put on it tomorrow so this proves to me that what Roy has come up with works....well....I am anxiously waiting to see how this improves the sound on this speaker. Thanks again Roy! Link to comment Share on other sites More sharing options...
RoyC Posted July 20, 2012 Report Share Posted July 20, 2012 I am one of those who is using Roy's sealant for my A2. I put the first coat on yesterday and after reading this thread, I went out to the workroom to see how it is curing. Much to my surprise when I did the three finger push in test, it is returning much slower than it was originally. I still have a second coat to put on it tomorrow so this proves to me that what Roy has come up with works....well.... I am anxiously waiting to see how this improves the sound on this speaker. Thanks again Roy!That's good news! I'm glad it is working out for you. As long as the woofer is returning slower than it would outside the cabinet, you are good to go.Roy Link to comment Share on other sites More sharing options...
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