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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
Posted to rec.audio.tech, sci.electronics.repair, uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
I recently found a very clean pair of JBL L19 speakers. These speakers look new. Before buying them, I examined the speaker surrounds thoroughly. All of them appear to be in perfect condition. I took them home and hooked them up. They sound very good, but I am hearing a slight rattle coming from one of the woofers. The rattle is not very loud at all, and in fact is almost inaudible most of the time. But you can definitely hear it if you are listening to certain things like a bass-heavy radio announcer's voice or a soft piano solo. The woofers on the JBL L19's have a bowl-shaped piece of paper glued to the center of the cone. I have verified that the glue is solid all the way around; I have even run a very fine bead of glue left over from a speaker surround kit all the way around the bowl, but the rattle persists. I can make the rattle go away if I gently put my finger on certain places in the center of the woofer cone. I can make the rattle worse if I put my finger on the surround, near the top of the speaker. One more thing: I can hear a slight rubbing noise if I gently push the woofer's cone back and forth on the top half of the speaker. I do NOT hear this rubbing noise if I push the cone anywhere on the bottom half, and I do NOT hear the rubbing noise if I push both the top and bottom halves at the same time (in other words, if I push the cone in a "balanced" way). I have verified that NOTHING is touching the back of the speaker; no wires, no insulation or anything else. I am suspecting that maybe the spider is out of round or off-center, or maybe the voice coil is off-center. What can I do to further diagnose, and then fix, this annoying problem? |
#2
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
On Mon, 14 Jan 2008 07:16:19 -0800 (PST), EADGBE
wrote: I recently found a very clean pair of JBL L19 speakers. These speakers look new. Before buying them, I examined the speaker surrounds thoroughly. All of them appear to be in perfect condition. I took them home and hooked them up. They sound very good, but I am hearing a slight rattle coming from one of the woofers. The rattle is not very loud at all, and in fact is almost inaudible most of the time. But you can definitely hear it if you are listening to certain things like a bass-heavy radio announcer's voice or a soft piano solo. The woofers on the JBL L19's have a bowl-shaped piece of paper glued to the center of the cone. I have verified that the glue is solid all the way around; I have even run a very fine bead of glue left over from a speaker surround kit all the way around the bowl, but the rattle persists. I can make the rattle go away if I gently put my finger on certain places in the center of the woofer cone. I can make the rattle worse if I put my finger on the surround, near the top of the speaker. One more thing: I can hear a slight rubbing noise if I gently push the woofer's cone back and forth on the top half of the speaker. I do NOT hear this rubbing noise if I push the cone anywhere on the bottom half, and I do NOT hear the rubbing noise if I push both the top and bottom halves at the same time (in other words, if I push the cone in a "balanced" way). I have verified that NOTHING is touching the back of the speaker; no wires, no insulation or anything else. I am suspecting that maybe the spider is out of round or off-center, or maybe the voice coil is off-center. What can I do to further diagnose, and then fix, this annoying problem? When the rubbing is very slight you can usually cure it by unbolting the speaker, rotating it 180 degrees and bolting it back in. Everything sags slightly the other way and bits that were touching stop doing so. d -- Pearce Consulting http://www.pearce.uk.com |
#3
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
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#4
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
On Mon, 14 Jan 2008 07:16:19 -0800 (PST), EADGBE
wrote: I am suspecting that maybe the spider is out of round or off-center, or maybe the voice coil is off-center. What can I do to further diagnose, and then fix, this annoying problem? One easy thing to try is to mount the speaker the other way up. Otherwise get it re-coned. This may or may not be cost-effective. |
#5
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
EADGBE wrote: I recently found a very clean pair of JBL L19 speakers. These speakers look new. Before buying them, I examined the speaker surrounds thoroughly. All of them appear to be in perfect condition. I took them home and hooked them up. They sound very good, but I am hearing a slight rattle coming from one of the woofers. The rattle is not very loud at all, and in fact is almost inaudible most of the time. But you can definitely hear it if you are listening to certain things like a bass-heavy radio announcer's voice or a soft piano solo. The woofers on the JBL L19's have a bowl-shaped piece of paper glued to the center of the cone. I have verified that the glue is solid all the way around; I have even run a very fine bead of glue left over from a speaker surround kit all the way around the bowl, but the rattle persists. I can make the rattle go away if I gently put my finger on certain places in the center of the woofer cone. I can make the rattle worse if I put my finger on the surround, near the top of the speaker. One more thing: I can hear a slight rubbing noise if I gently push the woofer's cone back and forth on the top half of the speaker. I do NOT hear this rubbing noise if I push the cone anywhere on the bottom half, and I do NOT hear the rubbing noise if I push both the top and bottom halves at the same time (in other words, if I push the cone in a "balanced" way). I have verified that NOTHING is touching the back of the speaker; no wires, no insulation or anything else. I am suspecting that maybe the spider is out of round or off-center, or maybe the voice coil is off-center. What can I do to further diagnose, and then fix, this annoying problem? More than likely, the speaker was overdriven and the voice coil hit the pole piece and warped the coil. Recone or replacement is the only solution then. There is a chance that the spider has come unglued. CHeck under the cone in the basket area to confirm the spider is firmly connected to the cone and the speaker basket. I have not seen this in a JBL, but i have seen it before (not very often though) Speakers of the 10/15 year old vintage often suffer from dry rot of the cone surround. Check closely for any MICRO fracture of where the surround connects to the basket or the cone itself. THis is the first stage of self destruction. bob |
#6
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"EADGBE" wrote in message ... I recently found a very clean pair of JBL L19 speakers. These speakers look new. snip According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... |
#7
Posted to rec.audio.tech, sci.electronics.repair, uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
On Jan 14, 11:19 am, "Keith G" wrote:
According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ....And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. |
#8
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... |
#9
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
In article ,
Keith G wrote: The words '**** off spammer' spring immediately to mind... A strange spammer who isn't trying to sell or promote anything... -- *If PROGRESS is for advancement, what does that make CONGRESS mean? Dave Plowman London SW To e-mail, change noise into sound. |
#10
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"Keith G" wrote in message ... "EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... Hi Keith - long time no speak. How's it hanging ? Missus OK ? FWIW, this guy posts often on s.e.r. and I have never known him to be impolite or to fail to acknowledge any responders to his questions, myself included. Arfa |
#11
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"Arfa Daily" wrote in message ... "Keith G" wrote in message ... "EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... Hi Keith - long time no speak. How's it hanging ? Missus OK ? FWIW, this guy posts often on s.e.r. and I have never known him to be impolite or to fail to acknowledge any responders to his questions, myself included. Hi Arfa! All is well here, thanks - hope the same with you! (Dinky little drive belt continues to work perfectly!) Anyway, regarding our Guitar String friend (that anyone should be so quick to support me when U No Hoo is flicking his little calumnies my way!) - as I said above: On my machine (which is new, so it don't go back all the way to the Big Bang) I have only one former entry which shows another instance of him crossposting a request for advice and no sign of a response of any kind to the 4 replies he received: http://www.apah69.dsl.pipex.com/show/ukra.jpg I speak as I find...!! |
#12
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"Meat Plow" wrote in message ... On Mon, 14 Jan 2008 18:24:25 +0000, Keith G wrote: "EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... I've known EADGBE to be anything but a spammer. Who the **** cares - I have clear evidence that he's a twice a year blow-in wanting free advice and obviously doesn't consider it ill-mannered to smear it all over several separate newsgroups to get what he wants and without a word of thanks. Look at the pic: http://www.apah69.dsl.pipex.com/show/ukra.jpg Work it out for yourself.... Delete 'spammer' and insert 'crossposter' if it makes you feel better - usenet tosser, either way.... Maybe it's you who should **** off... From ukra - the only group I subscribe to? (See also in the pic...) Stop and have a little think, YTC - you stop crossposting here and I don't even *see* your silly posts... (Yes, my replies are also crossposted - how TF do I know where you are posting from...???) |
#13
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"Keith G" wrote in message ... "Meat Plow" wrote in message ... On Mon, 14 Jan 2008 18:24:25 +0000, Keith G wrote: "EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... I've known EADGBE to be anything but a spammer. Who the **** cares - I have clear evidence that he's a twice a year blow-in wanting free advice and obviously doesn't consider it ill-mannered to smear it all over several separate newsgroups to get what he wants and without a word of thanks. Look at the pic: http://www.apah69.dsl.pipex.com/show/ukra.jpg Work it out for yourself.... Delete 'spammer' and insert 'crossposter' if it makes you feel better - usenet tosser, either way.... Maybe it's you who should **** off... From ukra - the only group I subscribe to? (See also in the pic...) Stop and have a little think, YTC - you stop crossposting here and I don't even *see* your silly posts... (Yes, my replies are also crossposted - how TF do I know where you are posting from...???) Maybe your news server just didn't see his reply or it didn't get crossposted? I see a few regulars in that reply from s.e.r.. I know that EADGBE isn't a spammer / Troll as well. If you upset because it is crossposted, create a filter. Theres no need to get angry about it. Now to get this back on topic, Have you tried moving the voice coil in and out by hand to feel if it it is dragging at all? I'd tend to agree with the others that the cone might be out of alignment a bit. Mike |
#14
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
"Meat Plow" wrote in message ... On Tue, 15 Jan 2008 23:59:17 +0000, Keith G wrote: "Meat Plow" wrote in message ... On Mon, 14 Jan 2008 18:24:25 +0000, Keith G wrote: "EADGBE" wrote in message ... On Jan 14, 11:19 am, "Keith G" wrote: According to my reader, the last time this crossposting clown posted in ukra was 18/05/07 to ask for free advice with questions about more dodgy old gear, splashed across a different spread of newsgroups and then failed to acknowledge the bunch of helpful replies he received.... Hmmm.... Then you don't know how to read your reader, asshole. If you ACTUALLY did the research you claim to have done, you will find that I have consistently and publicly thanked the people who took the time to help me. ...And I will thank YOU to keep your smart-ass comments to yourself in the future. This is the last you'll hear from me. If you want to satisfy your juvenile urge to flame me some more, go right ahead. I won't take the bait. Have a nice day. The words '**** off spammer' spring immediately to mind... I've known EADGBE to be anything but a spammer. Who the **** cares I care. And who the **** cares whether you care or not. And you've caused much more noise than EADGBE so kindly **** off. No, **** - you have. Keep crossposting into ukra to prove me right.... snipped the rest of your bull**** completely unread Nah, I don't believe you.... |
#15
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
EADGBE wrote:
They sound very good, but I am hearing a slight rattle coming from one of the woofers. The rattle is not very loud at all, and in fact is almost inaudible most of the time. But you can definitely hear it if you are listening to certain things like a bass-heavy radio announcer's voice or a soft piano solo. I had that effect in some Pioneer speakers way back when because the foam surround was coming loose from the cones. I would have sworn that the voice coils were warped and touching the magnet cores. -- If John McCain gets the 2008 Republican Presidential nomination, my vote for President will be a write-in for Jiang Zemin. |
#16
Posted to rec.audio.tech,sci.electronics.repair,uk.rec.audio,rec.audio.pro
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QUESTION: JBL Speaker Rattle
I have had this before. The speaker has to be re-coned, or the surround has
to be changed. There are a fair number of places that specialize in speaker driver rebuilding. The cone or the spider is off centre. As the drivers age, they can go off centre. Some people suggest turning them around in their mounts, but this does not properly fix the problem. When rebuilding a driver, I would have both re-built at the same time. This would insure that that they are matched. The other solution is to call the JBL rep and order a new driver. The fault you are having is common on many types of speakers. We send out speakers for rebuilding for our clients. -- JANA _____ "EADGBE" wrote in message ... I recently found a very clean pair of JBL L19 speakers. These speakers look new. Before buying them, I examined the speaker surrounds thoroughly. All of them appear to be in perfect condition. I took them home and hooked them up. They sound very good, but I am hearing a slight rattle coming from one of the woofers. The rattle is not very loud at all, and in fact is almost inaudible most of the time. But you can definitely hear it if you are listening to certain things like a bass-heavy radio announcer's voice or a soft piano solo. The woofers on the JBL L19's have a bowl-shaped piece of paper glued to the center of the cone. I have verified that the glue is solid all the way around; I have even run a very fine bead of glue left over from a speaker surround kit all the way around the bowl, but the rattle persists. I can make the rattle go away if I gently put my finger on certain places in the center of the woofer cone. I can make the rattle worse if I put my finger on the surround, near the top of the speaker. One more thing: I can hear a slight rubbing noise if I gently push the woofer's cone back and forth on the top half of the speaker. I do NOT hear this rubbing noise if I push the cone anywhere on the bottom half, and I do NOT hear the rubbing noise if I push both the top and bottom halves at the same time (in other words, if I push the cone in a "balanced" way). I have verified that NOTHING is touching the back of the speaker; no wires, no insulation or anything else. I am suspecting that maybe the spider is out of round or off-center, or maybe the voice coil is off-center. What can I do to further diagnose, and then fix, this annoying problem? |
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