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?

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

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

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.

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

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....

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.

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...

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.

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