QUESTION: JBL Speaker Rattle

[EADGBE]

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?

 

[Don Pearce]

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

 

[GregS]

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

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

 

[Laurence Payne]

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.

 

[Bob Urz]

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

 

[Keith G]

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....

 

[EADGBE]

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.

 

[Keith G]

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 'piss off spammer' spring immediately to mind...

 

[Dave Plowman (News)]

The words 'piss off spammer' spring immediately to mind...

A strange spammer who isn't trying to sell or promote anything...

 

[Arfa Daily]

The words 'piss 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

 

[clifto]

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.

 

[JANA]

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
_____



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?

 

[Keith G]

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...!!

 

[Arfa Daily]

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...!!

Fair enough , Keith. I would have to say that it was possibly an oversight
then, because as I said, I have typically found him to be a responsible
poster, definitely not in the class of 'spammer' or 'troll' ...

Glad you're all well, and the belt is still ok. Fleetie pops in over here
from time to time. I'll have to try to find the (computer) time to pop over
there again soon for a chat with all you guys.

Arfa

 

[Meat Plow]

The words 'piss off spammer' spring immediately to mind...

I've known EADGBE to be anything but a spammer. Maybe it's you who should
piss off...

 

[Keith G]

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

piss 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...???)

 

[Michael Kennedy]

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


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

 

[Keith G]

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.

Angry at newsgroup posts? Oh, I don't think so....

Please point to where my original response is incorrect:

"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...."

And then consider directing your advice to the root cause - ie, the
crossposter himself who, incidentally, responded to me with this little gem:

"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."

When the clear evidence:

http://www.apah69.dsl.pipex.com/show/ukra.jpg


indicates that a) I did do the research, b) your paragon failed to thank
anyone at least on that occasion and c) is, in fact, a crossposting little
gobshite who doesn't brook at dragging half Usenet into sorting out his
problems for free if, when and as he feels like it....

 

[Arfa Daily]

Angry at newsgroup posts? Oh, I don't think so....

Please point to where my original response is incorrect:

"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...."

And then consider directing your advice to the root cause - ie, the
crossposter himself who, incidentally, responded to me with this little
gem:

"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."

When the clear evidence:

http://www.apah69.dsl.pipex.com/show/ukra.jpg


indicates that a) I did do the research, b) your paragon failed to thank
anyone at least on that occasion and c) is, in fact, a crossposting little
gobshite who doesn't brook at dragging half Usenet into sorting out his
problems for free if, when and as he feels like it....

Hey ! I've never seen you getting this worked up Keefy baby ! Those good 'ol
Aussie boys on ukra been giving you lessons or summat ? d;~}

Arfa

 

[Bob Shuman]

Keith,

It seems to me like you are digging yourself a deeper hole with every reply.

From what I've read in the sci.electronics.repair newsgroup, EADGBE does not
qualify as a spammer and prior to his response to you, thanked contributors
and kept things civil.

The record on this particular news thread speaks for itself.

Bob