Anyone who has been dealing with the repair of loudspeakers is aware of the
huge increases in reconing charges by manufacturers like Electro-Voice, JBL
and Altec.

For instance, E-V's charge for reconing an 18B low frequency reproducer was
$64.13 for many years. Then the late 1980s saw that price increase. The last
time I had them recone a driver was around 1995, at over three times the
price!

Same situation with the other companies.

The cost is so high now that we have been buying up closeout speakers for
less than the cost of reconing the speakers we bought from Altec/E-V and
others. I mean, when you can pick up a closeout special for an 18" driver
for $100, why spend $189 to get your E-V driver reconed, right? :-)

I've accumulated a rather large quantity of blown E-V 18B woofers and Altec
3182 woofers. They have been sitting, unrepaired, for about ten years,
because of the prohibitive costs of reconing. However, realizing that the
cost isn't going to go down, but up, I am considering getting these
repaired. But before I blow a grand on repairs from the original
manufacturers, I want to find out if there are less expensive recone options
for these drivers.

If I could get these drivers reconed for about $100 a piece, with factory
parts at the same quality as a factory recone, I would do it in a heartbeat.
But I don't know of any resources that will do this. So I'm putting the
question to the forum. I hope to hear some success stories with finding a
good vendor.




--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

Mark & Mary Ann Weiss wrote:

I've accumulated a rather large quantity of blown E-V 18B woofers and Altec
3182 woofers. They have been sitting, unrepaired, for about ten years,
because of the prohibitive costs of reconing. However, realizing that the
cost isn't going to go down, but up, I am considering getting these
repaired. But before I blow a grand on repairs from the original
manufacturers, I want to find out if there are less expensive recone options
for these drivers.

Try Cardinal Motion Picture and Sound Services in Baltimore. They are
authorized JBL and Altec dealers and Steve, the speaker tech there, has
been to JBL and Altec recone school. He does good work. He may not be
much cheaper than the original manufacturers, though, if he uses original
parts from the manufacturer.

My general experience is that the only supplier of third-party recone kits
in the US is Waldom, and their stuff is often flaky at best. Replacement
surrounds are usually okay, but matching a voice coil is usually doubtful
and complete cone assembly replacement almost always turns out to be much
worse than using the OEM parts.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Fri, 11 Mar 2005 02:37:54 GMT, "Mark & Mary Ann Weiss"
wrote:

If I could get these drivers reconed for about $100 a piece, with factory
parts at the same quality as a factory recone, I would do it in a heartbeat.
But I don't know of any resources that will do this. So I'm putting the
question to the forum. I hope to hear some success stories with finding a
good vendor.

Dave Miller in Tulsa would be my first call. He can also tell you
tales about where the parts from Oklahoma City went and who's
still got some. Speakerworks (800) 526-8879. And the caliber
of weapons involved.

Is that $100 with or without shipping both ways?
Good fortune,

Chris Hornbeck

If I could get these drivers reconed for about $100 a piece, with factory
parts at the same quality as a factory recone, I would do it in a
heartbeat.
But I don't know of any resources that will do this. So I'm putting the
question to the forum. I hope to hear some success stories with finding a
good vendor.

Dave Miller in Tulsa would be my first call. He can also tell you
tales about where the parts from Oklahoma City went and who's
still got some. Speakerworks (800) 526-8879. And the caliber
of weapons involved.

Is that $100 with or without shipping both ways?
Good fortune,

Chris Hornbeck

Thanks for all the replies so far.
It looks like there are no real bargains out there, relative to having the
manufacturer do the repairs. Prices have just inflated a lot in the past two
decades. Reconing is one area that has seen upwards of 300% inflation.
I was quoting the repair charge separate from shipping (another small
fortune). I can remember when I could ship an 18B in orginal factory box, to
Buchannan, Mich for just $28, UPS Ground. Today it would probably be more
like $50 each way. No wonder eBay has so many 'blown' drivers up for auction
these days. :-)


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

In article writes:

It looks like there are no real bargains out there, relative to having the
manufacturer do the repairs. Prices have just inflated a lot in the past two
decades. Reconing is one area that has seen upwards of 300% inflation.

Well, that's not a lot more than inflation of a lot of other things.
Also, in addition to the cost of the parts (and everything costs less
than the sum of its parts cost) there's a craft to be learned, and one
that's probably slowly dyning. All too many people are blowing
speakers today, and instead of reconing, just replace either the
driver (often seeking out something less expensive than the original)
or replacing the entire speaker. So there really isn't much of a
resource left other than the factory - and they aren't going to
interrupt the assembly line flow to recone a speaker unless they can
make enough money by doing so to make it worth while (hence the
seemingly high cost).

Why are you blowing so many speakers anyway?

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

On Fri, 11 Mar 2005 09:42:41 GMT, "Mark & Mary Ann Weiss"
wrote:

...

Thanks for all the replies so far.
It looks like there are no real bargains out there, relative to having the
manufacturer do the repairs. Prices have just inflated a lot in the past two
decades. Reconing is one area that has seen upwards of 300% inflation.
I was quoting the repair charge separate from shipping (another small
fortune). I can remember when I could ship an 18B in orginal factory box, to
Buchannan, Mich for just $28, UPS Ground. Today it would probably be more
like $50 each way.

What about doing the recones yourself? Presuming you're not making
more money doing something else, you can save doing this. Since you
have a backlog of these, it seems it could be well worth your time to
go through the learning curve. It would certainly save on the shipping
charges as well as paying someone else's price to do them.
I've seen reconing sites on the web (both they-do-it and
you-learn-how-to-do-it), but I have no clue if they have 18" parts or
if they're as good as factory parts.

No wonder eBay has so many 'blown' drivers up for auction
these days. :-)


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-



-----
http://mindspring.com/~benbradley

"Mike Rivers" wrote in message
news:znr1110546038k@trad...

In article
writes:

It looks like there are no real bargains out there, relative to having
the
manufacturer do the repairs. Prices have just inflated a lot in the past
two
decades. Reconing is one area that has seen upwards of 300% inflation.

Well, that's not a lot more than inflation of a lot of other things.
Also, in addition to the cost of the parts (and everything costs less
than the sum of its parts cost) there's a craft to be learned, and one
that's probably slowly dyning. All too many people are blowing
speakers today, and instead of reconing, just replace either the
driver (often seeking out something less expensive than the original)
or replacing the entire speaker. So there really isn't much of a
resource left other than the factory - and they aren't going to
interrupt the assembly line flow to recone a speaker unless they can
make enough money by doing so to make it worth while (hence the
seemingly high cost).

Interesting points. And knowing a bit about how factories work, I understand
why the costs are so high. However, I was under the impression the big
manufacturers had a dedicated repair division. Isn't that what Telex/EVI
Audio is doing?


Why are you blowing so many speakers anyway?

Not really blowing that many. These accumulated since 1995.
But I'll describe:

Mostly poorer quality rebuilds. Case in point. E-V started reconing their
18B drivers with a much stiffer, less compliant suspension in the early
1990s. We started to see a lot of thermal failures on the reconed drivers
from that point onward. They simply were so stiff they could not move enough
to air cool their voice coils.
Other drivers failed because of voice coil former hitting the side of pole
piece.
The Altec 3182s were very sensitive to this issue, prompting us to design an
optical limiter system and installed LED/photocell pairs on the cones/spider
seats of these drivers, which alleviated the problem.
Another isidious new problem with Eminence drivers is the use of
cyanoacrylate-type adhesives to bond the Kapton voice coil former to the
cone & spider assy. Unlike the conventional adhesives which were tenatious,
cyanacrylate is brittle, and once broken, loses all bond. Eminence cites the
use as a cost-saving measure.
Our latest remedy to combat problems, while yielding more SPLs, was to
install a digital Loudspeaker Management System. This has been a tremendous
help.

I'll admit: we do push them hard. But we're packed wall to wall with
speakers here, and can't fit anymore in the space available!


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

What about doing the recones yourself? Presuming you're not making
more money doing something else, you can save doing this. Since you
have a backlog of these, it seems it could be well worth your time to
go through the learning curve. It would certainly save on the shipping
charges as well as paying someone else's price to do them.
I've seen reconing sites on the web (both they-do-it and
you-learn-how-to-do-it), but I have no clue if they have 18" parts or
if they're as good as factory parts.

I gave that a brief thought. I also found some speaker parts distributors,
but it seems you have to be an authorized repair shop to buy from them.

I have no problem with doing the recones myself, as long as I don't need to
invest in special ovens or other expensive equipment specific to the repair
industry.

In fact, I have done several surgical repairs on woofers over the past 6
years with great success. Last month, I repaired a 4" voice coil that had
struck the outer edge of the pole piece assembly, causing an arc weld at
that point. I managed to salvage the lead and the driver is working fine,
albeit with 180º polarity reversal, requiring rewiring of the terminals.
I've repaired countless drivers from 8" to 18" for the Kapton/cyanoacrylate
adhesive failure, by injecting silicon rubber adhesive through the mesh of
the spider and into the gap between the former and the spider/cone apex,
using a hyperdermic needle. I can't tell you how many Chinese import
speakers I've repaired this way. :-)
Believe me, if I could get top quality kits, I'd gladly do it myself and
save. I service all the amplifiers as it is, and feel a bit taken advantage
of by the price of reconing.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

Mark & Mary Ann Weiss wrote:
I gave that a brief thought. I also found some speaker parts distributors,
but it seems you have to be an authorized repair shop to buy from them.

Call Image Communications. They will set you up as a Waldom authorized
repair shop for fifty bucks if there are no others in your immediate area.

The problem is that they won't send you to speaker school, and you will
still only be able to get Waldom parts rather than the original OEM parts.
From your description of the crap you're getting from EV, though, the
Waldom stuff might be an improvement.

Have you considered taking the stiffer spiders from EV and razor-blading
them down a little bit and making them less compliant? I am thinking you
might even be able to do it without disassembling the drivers.

Believe me, if I could get top quality kits, I'd gladly do it myself and
save. I service all the amplifiers as it is, and feel a bit taken advantage
of by the price of reconing.

NOBODY can get top quality kits for some of the older drivers out there,
which is a big issue.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article et writes:

I was under the impression the big
manufacturers had a dedicated repair division. Isn't that what Telex/EVI
Audio is doing?

I don't know what's going on today. I do know that the cost of getting
an EV microphone repaired, which until just a couple of years ago
ranged from zilch to trivial has become real money. Many "big"
manufacturers have outsourced repairs recently for a few reasons, some
of which apply to EV, some of which don't. Take your pick:

- Much of the manufacturing is outsourced now, so they don't need as
much machinery, staff, or plant space that they used to. Lose too
much of that and you lose your capability to do repairs in house.

- The bulk of their products are essentially unrepairable (doesn't
necessarily apply to speakers) so they don't maintain a repair
department other than as a courtesy to customers who don't have
enough sense to throw the junk away and buy something else.

- Because of the above, more people are inclined to throw the junk
away, so the repair traffic has slowed. It costs more per repair
because the cost of facilities doesn't drop significantly until you
get rid of the facility.

E-V started reconing their
18B drivers with a much stiffer, less compliant suspension in the early
1990s. We started to see a lot of thermal failures on the reconed drivers
from that point onward. They simply were so stiff they could not move enough
to air cool their voice coils.

They probably thought they were doing the right thing, but that sounds
kind of fishy. Seems that they'd know about that. Maybe they found
that they were having more failures that resulted from

Other drivers failed because of voice coil former hitting the side of pole
piece.

so they decided that it would be a good idea to reduce that failure
mode. But I guess if you push your speakers closer to the limit due to
the lower compliance, and hence lower sensitivity (after all, it has
to get as loud as it used to, probably louder), you run the risk of
thermal damage.

I'll admit: we do push them hard. But we're packed wall to wall with
speakers here, and can't fit anymore in the space available!

Sell 'em on eBay. g



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article et writes:

I gave that a brief thought. I also found some speaker parts distributors,
but it seems you have to be an authorized repair shop to buy from them.

I have no problem with doing the recones myself, as long as I don't need to
invest in special ovens or other expensive equipment specific to the repair
industry.

Have you investigated being an authorized repair shop? Sometimes it's
as simple as sending them a copy of your business license. A local
sound company that some friends of mine owned were "authorized" JBL
and EV repair shops so they could get parts to recone their own
speakers. They didn't do it for anyone else though, other than
friends. That was upwards of 20 years ago, but I figure that if there
are parts available, they'll sell them. They just want to know who's
doing what.

It sounds like you're fully qualified to do the work. No reason why
you shouldn't be able to get parts if they're available.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

I don't know what's going on today. I do know that the cost of getting
an EV microphone repaired, which until just a couple of years ago
ranged from zilch to trivial has become real money. Many "big"
manufacturers have outsourced repairs recently for a few reasons, some
of which apply to EV, some of which don't. Take your pick:

Yes, I'm familiar with the repair issues on the RE-20, for instance. My main
line of business is broadcast engineering services. That ranges from RF
transmitter repairs to studio construction and repairs of studio gear. Three
years ago, one of my radio clients approached me to repair a few RE-20 mics.
They didn't want to pay E-V's repair fees, which were in the hundreds of
dollars per mic. In many cases, it was just a matter of repairing twisted
internal wiring and tightening the base and also replacing the foam around
the capsule. I did all those repairs for a mere $50/hour charged. So they
got three mics repaired for the price of one done at E-V.
Perhaps E-V outsourced the mic repairs recently. If so, that's a bad thing
for owners.
But I'm already seeing a lot of clients embrace high quality, made in China
products, like the Behringer mics, which, IMHO, are quite excellent. And for
a fraction the cost of the E-Vs, some stations are simply replacing their
mics rather than repairing.


- Much of the manufacturing is outsourced now, so they don't need as
much machinery, staff, or plant space that they used to. Lose too
much of that and you lose your capability to do repairs in house.

- The bulk of their products are essentially unrepairable (doesn't
necessarily apply to speakers) so they don't maintain a repair
department other than as a courtesy to customers who don't have
enough sense to throw the junk away and buy something else.

- Because of the above, more people are inclined to throw the junk
away, so the repair traffic has slowed. It costs more per repair
because the cost of facilities doesn't drop significantly until you
get rid of the facility.

Understood. In that case, I had better hurry up and recone all of the
drivers I have sitting in storage here, before it's too late.


E-V started reconing their
18B drivers with a much stiffer, less compliant suspension in the early
1990s. We started to see a lot of thermal failures on the reconed
drivers
from that point onward. They simply were so stiff they could not move
enough
to air cool their voice coils.

They probably thought they were doing the right thing, but that sounds
kind of fishy. Seems that they'd know about that. Maybe they found
that they were having more failures that resulted from

Other drivers failed because of voice coil former hitting the side of
pole
piece.

so they decided that it would be a good idea to reduce that failure
mode. But I guess if you push your speakers closer to the limit due to
the lower compliance, and hence lower sensitivity (after all, it has
to get as loud as it used to, probably louder), you run the risk of
thermal damage.

Their earlier 18B drivers had nice compliance, but some of the recones were
off-center, resulting in rubbing of the coil former with the pole surround
at moderate excursions.

But I can't see how reducing the compliance drastically would increase
efficiency. If anything, we have had to increase power through the use of
EQ, to restore some of the lost bottom end, exasperating the problem even
more.



I'll admit: we do push them hard. But we're packed wall to wall with
speakers here, and can't fit anymore in the space available!

Sell 'em on eBay. g

I think I wasn't clear in my statement. The reason we have so many speakers
is to achieve the SPLs. We have to get as much as possible out of each
driver, because we can't simply up the number of drivers. g

At one point, I was seriously considering importing drivers from a British
company call Precision Devices. They make drivers with up to 6" voice coils
and 4,000 watts continuous power handling. However, I dread the thought of
having to ever ship one of those back to England for reconing, should the
need arise.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

Mark & Mary Ann Weiss wrote:
I gave that a brief thought. I also found some speaker parts
distributors,
but it seems you have to be an authorized repair shop to buy from them.

Call Image Communications. They will set you up as a Waldom authorized
repair shop for fifty bucks if there are no others in your immediate area.

The problem is that they won't send you to speaker school, and you will
still only be able to get Waldom parts rather than the original OEM parts.
From your description of the crap you're getting from EV, though, the
Waldom stuff might be an improvement.

That might be an option cheap enough to try once. However, this is an
operation where even slightly inferior components cannot be tolerated. The
parts have to be as good as E-V, Altec and JBL originals.

And don't we need to use an oven to cure the glues after reconing? This
could involve a costly amount of capital equipment for an experiment that is
not likely to yield great results.


Have you considered taking the stiffer spiders from EV and razor-blading
them down a little bit and making them less compliant? I am thinking you
might even be able to do it without disassembling the drivers.

Absolutely not. Razoring the spiders not only would void the warranty, but
it would remove the mechanism that prevents the voice coil from moving
laterally during its excursion. The spider is also just a small part of the
stiffness problem. The outer surrounds on the new E-V cone kits are also to
blame.
We have tried break in conditioning of drivers, and even in free air, they
have so little compliance that thermal breakdown occurs before substantial
excursions can be achieved.
I have been thinking about settup on an Isobarik chamber, into which the new
driver to be broken in is mounted and gets passively driven by another,
higher compliance driver. Perhaps it could be drive with 1/4 the power
applied to the active driver, to assist it, but the bulk of the mechanical
movement would come from another driver. Put it in the chamber for ten
minutes and let it get a few thousand cycles of full motion to loosen the
suspension up. That is my only solution to preparing new drivers safely for
use.
The first time we got an 18BX driver in, it was extremely stiff. So it was
fed 1-second durations of 20 hertz at 100 watts of power, in free air,
cycled at 1-second intervals, for a 50% duty cycle. The cone was so stiff it
barely moved, and in about 10 seconds of break in, the voice coil had
fractured. Earlier drivers did not need conditioning to get the free air
resonance down to the Theile-Small parameters shown on the specification
sheet. They were supplied at-spec from the factory. The new drivers are a
full octave above the stated Fs, which is a real problem.


Believe me, if I could get top quality kits, I'd gladly do it myself and
save. I service all the amplifiers as it is, and feel a bit taken
advantage
of by the price of reconing.

NOBODY can get top quality kits for some of the older drivers out there,
which is a big issue.
--scott

Nobody but the original manufacturers, that is. And even with the way they
are going, it's starting to look more challenging to get a good recone, even
from E-V, Altec, et al.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

Have you investigated being an authorized repair shop? Sometimes it's
as simple as sending them a copy of your business license. A local
sound company that some friends of mine owned were "authorized" JBL
and EV repair shops so they could get parts to recone their own
speakers. They didn't do it for anyone else though, other than
friends. That was upwards of 20 years ago, but I figure that if there
are parts available, they'll sell them. They just want to know who's
doing what.

It sounds like you're fully qualified to do the work. No reason why
you shouldn't be able to get parts if they're available.


That thought crossed my mind and indeed has become a practical philosophy
(for instance, we had to repair some SMD components on some equipment, so
rather than send it out for repair, we invest in a SMD hot air soldering
station and sell the services to others as an addition to what we do), but I
wonder how much more I want to diversify than what I am already covering.
And we have four different makes of speakers to be reconed, making the kit
obtaining process multiplied by four suppliers possibly.

And isn't is necessary to cure these things in an industrial oven? If memory
serves me, a reconing outfit once told me they bake the glue at some
elevated temperature for a period of time. When it starts to involve this
much capital equipment, I can no longer think of it as an in-house-only
service. It has to become a profitable venture.

Nice ideas, either way.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

Mark & Mary Ann Weiss wrote:

NOBODY can get top quality kits for some of the older drivers out there,
which is a big issue.

Nobody but the original manufacturers, that is. And even with the way they
are going, it's starting to look more challenging to get a good recone, even
from E-V, Altec, et al.

The original manufacturers, as you point out, are often shipping totally
inappropriate substitutes these days because they cannot get appropriate
parts for the older drivers.

It's not a matter of it getting expensive, it's a matter of stuff that you
just cannot get no matter how much you're willing to spend
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Mark & Mary Ann Weiss wrote:

And isn't is necessary to cure these things in an industrial oven? If
memory
serves me, a reconing outfit once told me they bake the glue at some
elevated temperature for a period of time. When it starts to involve
this
much capital equipment, I can no longer think of it as an
in-house-only
service. It has to become a profitable venture.

I did Waldom/EV/Yammy recone service at the shop
I worked at through the 80's. I never saw or used
any such oven. Since permanent magnets and high
temperatures above a certain degree don't get along
I'm not sure how well this would work. We did use a
heat lamp at times to speed up the glue when someone
needed to play through a fresh recone that night.
(not recommended)

Waldom vs EV, JBL, etc:
Various Waldom parts were a better match to the
originals than others. Some parts seemed to be OEM
with Waldom part #'s stamped. Others were vague
approximations that could be made to work. Quite
often I would use (for example) EV coils and glue
with Waldom cones and spiders.
In the late 80's Waldom developed a range of
flatwire coils that were decent replacements for
the EV and JBL parts. Prior to that many JBL recones
were done using the Waldom roundwire coils, hence
the lesser quality of some of the aftermarket jobs.
The customer gets what he pays for.
(JBL parts being more expensive)
I would expect that the current parts from Waldom
would be acceptable.

Check out the Speaker Shop for another possible
service source. He's got experience with large
touring systems. disclaimer: no affiliation,
just a guy I went to school with:

http://www.speakershop.com/


Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
-

rd

RD Jones wrote:

I did Waldom/EV/Yammy recone service at the shop
I worked at through the 80's. I never saw or used
any such oven. Since permanent magnets and high
temperatures above a certain degree don't get along
I'm not sure how well this would work. We did use a
heat lamp at times to speed up the glue when someone
needed to play through a fresh recone that night.
(not recommended)

SOME of the older manufacturer-recommended cements required baking to
stabilize them. I don't think this is really the case any more, although
some folks are using UV-curing epoxies for quick voice coil assembly work.

I think you could skip the UV-cure for occasional work, although it would
take an overnight cure for a lot of things that would otherwise take ten
minutes. Probably fine for the kind of volumes the original poster is
talking about.

Waldom vs EV, JBL, etc:
Various Waldom parts were a better match to the
originals than others. Some parts seemed to be OEM
with Waldom part #'s stamped. Others were vague
approximations that could be made to work. Quite
often I would use (for example) EV coils and glue
with Waldom cones and spiders.
In the late 80's Waldom developed a range of
flatwire coils that were decent replacements for
the EV and JBL parts. Prior to that many JBL recones
were done using the Waldom roundwire coils, hence
the lesser quality of some of the aftermarket jobs.
The customer gets what he pays for.
(JBL parts being more expensive)
I would expect that the current parts from Waldom
would be acceptable.

For older drivers, the Waldom stuff often isn't even close. Some bad
examples are the Altec 600 drivers and the Altec BiFlex drivers. As far
as I know, there is no appropriate BiFlex replacement cone available today.

I am more and more becoming suspicious that the surround has less to do
with the total driver compliance than most folks think, and that replacing
surrounds with cheap generic equivalents really does less than you might
expect. I've recently done a bunch of instrument drivers and found the Fs
was in just the right place after using cheap foam replacements from Parts
Express. Using the OEM stuff I got identical results (although I must say
the OEM stuff looked a lot nicer and went on with less cutting and poking).

Check out the Speaker Shop for another possible
service source. He's got experience with large
touring systems. disclaimer: no affiliation,
just a guy I went to school with:

http://www.speakershop.com/

Also Gabriel Loudspeaker Service in Olson, CA, which does nice work with
the Altec stuff.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article . net writes:

I have been thinking about settup on an Isobarik chamber, into which the new
driver to be broken in is mounted and gets passively driven by another,
higher compliance driver. Perhaps it could be drive with 1/4 the power
applied to the active driver, to assist it, but the bulk of the mechanical
movement would come from another driver.

Would bolting two speakers together front-to-front work? I remember
hearing that Bozak used to break in speakers by connecting them to the
AC power line, but I think that's a folk tale.

The first time we got an 18BX driver in, it was extremely stiff. So it was
fed 1-second durations of 20 hertz at 100 watts of power, in free air,
cycled at 1-second intervals, for a 50% duty cycle. The cone was so stiff it
barely moved, and in about 10 seconds of break in, the voice coil had
fractured.

That doesn't even sound very useful as a speaker. It could have been
near dead out of the box. Did you give up after one, or did you have
others like that?


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article znr1110889254k@trad, Mike Rivers wrote:

Would bolting two speakers together front-to-front work? I remember
hearing that Bozak used to break in speakers by connecting them to the
AC power line, but I think that's a folk tale.

No, it makes sense, at least with a transformer or a bunch of drivers in
series so they only have 6V or 12V across them. That should loosen things
up a bit.

Is it really of benefit to sweep back and forth in frequency, or is a single
frequency signal good enough for break-in?

The first time we got an 18BX driver in, it was extremely stiff. So it was
fed 1-second durations of 20 hertz at 100 watts of power, in free air,
cycled at 1-second intervals, for a 50% duty cycle. The cone was so stiff it
barely moved, and in about 10 seconds of break in, the voice coil had
fractured.

That doesn't even sound very useful as a speaker. It could have been
near dead out of the box. Did you give up after one, or did you have
others like that?

Agreed, that sounds pretty worthless.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Mike Rivers wrote:


Would bolting two speakers together front-to-front work? I remember
hearing that Bozak used to break in speakers by connecting them to the
AC power line, but I think that's a folk tale.


1800 watts RMS into an 8-ohm driver? I want two!

In article writes:

Is it really of benefit to sweep back and forth in frequency, or is a single
frequency signal good enough for break-in?

I would think that whatever frequency gives you the most cone motion
would be the right thing. After all, the idea of "breaking in" a
speaker (if it's a legitimate notion at all) seems like it would be to
flex the suspension a lot. I'd think that the resonant frequency would
be good. That way you could get the most motion for the least power,
which would reduce the risk of melting the voice coil.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

On 15 Mar 2005 20:48:36 -0500, (Mike Rivers)
wrote:

I would think that whatever frequency gives you the most cone motion
would be the right thing. After all, the idea of "breaking in" a
speaker (if it's a legitimate notion at all) seems like it would be to
flex the suspension a lot. I'd think that the resonant frequency would
be good. That way you could get the most motion for the least power,
which would reduce the risk of melting the voice coil.

Sounds good to me. In free air drivers bigger than your fist
will flap around pretty good with not-scary electrical input.

In a better life, I once built a driver input QC rig for a
fancypants home speaker line (where the speakers cost more than
my home) that used lots of conventional dynamic drivers in vertical
lines. Yeah, I know, I know, but it *can* work.

I found that I couldn't reliably measure even F-sub-S without
specifying room temperature, break-in, phase of the moon, etc.
To say nothing of C-sub-MS. *After* our buying 10,000 of the
particular surrounds we wanted for the midrange drivers, about one
order of magnitude over lifetime requirements, the European midrange
driver builders smoothed out and delivered a beautiful device.

Set up a simple three-stage receipt winnowing. First, a "blur",
large amplitude, low frequency. Second, a sweep, from below to
above operating range. Third, polarity check. I used clip leads
to the driver, regular home light switches on a panel to switch
an oscillator, a swept oscillator, and a D battery, in turn.

Human operator, human ears, human fingertip.

In this environment, once everything was set up, I only
spot-checked drivers from batches for detailed characteristics.
Just burned in with a line frequency blur.

Chris Hornbeck
"That's where may forebears came from. Three of them
anyway. Who's been sleeping in my porridge?" -F&S

About five years ago I found myself at a flea market in Chicago (West
Side maybe?). There was a man with a booth there who was selling
drivers and doing repairs. I think he went by the name of 'Pops'.

Does anyone know what flea market I could find him at? That is if he is
still doing this work...

Thanks,
Peter

I would think that whatever frequency gives you the most cone motion
would be the right thing. After all, the idea of "breaking in" a
speaker (if it's a legitimate notion at all) seems like it would be to
flex the suspension a lot. I'd think that the resonant frequency would
be good. That way you could get the most motion for the least power,
which would reduce the risk of melting the voice coil.


Essentially the way we break in drivers is to set them up in free air, find
Fs, (often nearly an octave higher than the original spec sheet quotes) and
start pulse trains at 1-second intervals.

After the first 18BX died, I decided to stop power conditioning drivers like
that. Nowadays, we do it carefully by hand. It works, but it's less
effective than the old methods. We usually get Fs very close to factory
spec. It may be quoted at 50Hz, but out of the box be around 83Hz, and we
may get it down to 57Hz before we give up.

The possibility of bolting a high compliance drive to a lower compliance
driver is decent, assuming one has one available and of suitable diameter.
For instance, an Altec 3184, bolted to a E-V 18BX would probably work, using
the 3184 as the active element and providing 20% power @180º to the 18BX to
assist.

I'm very concerned about the quality of kits, because a bad kit means an
immediate failure. Like I said, we don't pamper our drivers--we extract
every decibel out of them that is possible. Drivers must have zero defects
and the ones that do seem to be lasting indefinately. I have some really
good recones that have lasted over ten years, despite the heavy use, whilst
I have others that fail just an hour after installation. Often you can tell
before you even hook one up. If the cone rubs when you manually move it in
and out, that's a time bomb. If they used cyanoacrylate adhesive on a Kapton
former, that's a voice coil/spider separation in the near future. A couple
of good, fast transients and that will come apart, as it does with the whole
line of Eminence pro drivers. I always end up taking those apart and pumping
them full of silicone rubber adhesive. They never come apart again.


--
Best Regards,

Mark A. Weiss, P.E.
www.mwcomms.com
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