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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Default 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?
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Default 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
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Default QUESTION: JBL Speaker Rattle

In article , (Don Pearce) wrote:
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.


Eyesight alone is not a judge of condition. If you poke at
them, they should not tear.

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.


That may work. If the voice coil is good, a suround repair could also center
the driver, but it may be a little more difficult to make it look orginal
when done due to the center piece.

greg
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Default 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.
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Default 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


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Default 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....

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Default 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.

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Default 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...


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Default 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.
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Posts: 6,772
Default 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




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Default 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...!!

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Default 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...???)



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Default 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


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Default 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....


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Default 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.


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Posts: 259
Default 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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