18SW100 noise. Help identify (video inside)
Last week I noticed one of my drivers making noise. It still plays all bass/sub-bass notes, yet accompanied by this noise. It's quite noticeable at lower input drive levels and sometimes goes away during certain sine tests with varying input voltage.
Could it be a burned or misaligned vc? Blown? I'm unfamiliar with this noise, so I'm reaching out to you for advice.
VIDEO
Last week I noticed one of my drivers making noise. It still plays all bass/sub-bass notes, yet accompanied by this noise. It's quite noticeable at lower input drive levels and sometimes goes away during certain sine tests with varying input voltage.
Could it be a burned or misaligned vc? Blown? I'm unfamiliar with this noise, so I'm reaching out to you for advice.
VIDEO
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Maybe some of this info will help:
I can also hear whatever is making noise when I manually pull up on the cone from its underside when connected to an amplifer that's turned on without signal present. It does not make the noise when the amp is off, nor when pressing down on the cone with the amp on or off. So, it only makes the sound when a powered up amplifier is connected and with positive cone movement (away from magnet). Makes me think VC related. Thoughts?
I can also hear whatever is making noise when I manually pull up on the cone from its underside when connected to an amplifer that's turned on without signal present. It does not make the noise when the amp is off, nor when pressing down on the cone with the amp on or off. So, it only makes the sound when a powered up amplifier is connected and with positive cone movement (away from magnet). Makes me think VC related. Thoughts?
Thanks for the reply.
Assuming that's what was happening, I have since contacted a couple places regarding the price/availability of B&C's service kit. One of two places I contacted (loudspeakersplus.com) does re-cones in-house.
Has anyone attempted a re-cone on a B&C driver of this magnitude? Much different than any decent how-to videos would show?
Assuming that's what was happening, I have since contacted a couple places regarding the price/availability of B&C's service kit. One of two places I contacted (loudspeakersplus.com) does re-cones in-house.
Has anyone attempted a re-cone on a B&C driver of this magnitude? Much different than any decent how-to videos would show?
It depends on the kit. Some kits offer the voice coil attached to the cone, whereas, others will require a full assembly ( cone, spider, voice coil ) . Also, you need to take cost into factor. If you are planning to ship the speaker for repair, it may cost slightly less having it repaired (shipping plus repair) than buying a brand new speaker.
The last speaker I had reconed was 1994 so, I cannot tell you where the prices stand in this day and age. You live in the States so you can shop around for the best price if loudspeakerplus is too dear.
The last speaker I had reconed was 1994 so, I cannot tell you where the prices stand in this day and age. You live in the States so you can shop around for the best price if loudspeakerplus is too dear.
Sounds like some sloughed off windings dragging. Check the dc resistance.
If the voice coil former is Kapton, it could have developed some "heat blisters".
I successfully sanded off the blisters on an EVX 150A by removing the dust cap, then inserting emery cloth sandpaper in the gap and playing 20 Hz sine wave tones while holding the emery cloth. After blowing the dust out, and re-attaching the voice coil, the speaker worked fine.
Of course, if the voice coil is wound inside and out of the former, that procedure won't work.
Still, there is a chance that some crud melted and is in the gap, so worth a try to remove the dust cap and see if you can remove debris with compressed air or masking tape.
That stinks. You'd expect some reliability with that kind of ($) driver.
Anyway, were these speakers under your watch at all times? Or were they out of your sight where someone could have abused them?
Anyway, were these speakers under your watch at all times? Or were they out of your sight where someone could have abused them?
Hi Art,
DC resistance: 5.5 ohms
Do you know of an appropriate how-to video for removing the dust cap or will most videos relate to this style driver?
Do you think it's weird the noise only happens during its positive stroke?
Hi m R g S r,
No, not at all times. I've come back to a heavily limiting amp rack (heavy limiting creates a lot of heat in the vc), but I don't blame anyone but myself. I could've been more clear of what I wanted from my partner and I could've made sure the DJ's levels were watched/controlled more carefully every night like we have for the last 6 years. I tell you, If there were 5 clip lights on a DJM-800, some "talent" still wouldn't have trouble lighting em all up (meaning, it sometimes takes a full half-turn of the DJ's channel gain knob to get em out of clip). Then again, we're not quite sure when this happened. We had been setting up this sub for our bi-weekly and the noise is kind of reminiscent of air coming through the handles on the bottom against the floor - so, we very well could've been using it like this for a while.
DC resistance: 5.5 ohms
Do you know of an appropriate how-to video for removing the dust cap or will most videos relate to this style driver?
Do you think it's weird the noise only happens during its positive stroke?
Hi m R g S r,
No, not at all times. I've come back to a heavily limiting amp rack (heavy limiting creates a lot of heat in the vc), but I don't blame anyone but myself. I could've been more clear of what I wanted from my partner and I could've made sure the DJ's levels were watched/controlled more carefully every night like we have for the last 6 years. I tell you, If there were 5 clip lights on a DJM-800, some "talent" still wouldn't have trouble lighting em all up (meaning, it sometimes takes a full half-turn of the DJ's channel gain knob to get em out of clip). Then again, we're not quite sure when this happened. We had been setting up this sub for our bi-weekly and the noise is kind of reminiscent of air coming through the handles on the bottom against the floor - so, we very well could've been using it like this for a while.
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If the DC resistance is the same as other speakers of the same type, that is a good sign.
No videos I know of for removing dust caps, it just takes a steady hand and a sharp blade, an X-acto knife works well, and makes it easier to keep the blade parallel to the cone surface.
If the dust cap is glued with epoxy, it safer to cut it out above the glue line, but if you are confident cut it off below, it will be easier to re-use it.
If an upper portion of the voice coil has sloughed off, it may drag on the forward stroke and go back in place on the return stroke.
It might be possible to glue the windings back by inserting plastic shims in the gap and using a syringe to put some high temp epoxy on the loose winding- make sure the epoxy does not stick to the shim material.
Crescendo, I do not know when you purchased these (or where), but this might be applicable to you (BEFORE YOU GO CUTTING THINGS)
http://www.parts-express.com/pedocs/warranty/bc-speakers-bc-manufacturer-warranty-4458.pdf
http://www.parts-express.com/pedocs/warranty/bc-speakers-bc-manufacturer-warranty-4458.pdf
Sorry, it doesn't tell me anything about the amp used...
sine143 previous post plays in your favor, if it applies.
Note that excursion also gets out of control at 20-25Hz, the cone exiting the gap, it all depends in the alignment and net volume you have, and protection... and I do not say more cause I don't know the conditions of your system and knowledge you have, if a mistake like that (in design/LF protection) was committed or not.
Guess I wasn't getting these updates. Sorry for the delay.
The sub still chugs along. We don't use it often, but there have been maybe 2 or 3 shows since posting this that it has performed at (at a lower drive level than normal). So far, so good.
Thanks for the warranty post. Had me looking a bit further to find B&C's Warranty Ruturn Guide.pdf
How likely is it that:
-the voice coil is rubbing the gap's surface, or
-there's blistering on the former facing the winding?
Both of these (and more) are covered under their warranty terms.
The sub still chugs along. We don't use it often, but there have been maybe 2 or 3 shows since posting this that it has performed at (at a lower drive level than normal). So far, so good.
Thanks for the warranty post. Had me looking a bit further to find B&C's Warranty Ruturn Guide.pdf
How likely is it that:
-the voice coil is rubbing the gap's surface, or
-there's blistering on the former facing the winding?
Both of these (and more) are covered under their warranty terms.
it looks like a bild up heat spot,wich causes a loose wire or a blister.
wouldn't hurt to try to get warrenty.
if not ,try the things art sugested.
if al fails recone it.]
wouldn't hurt to try to get warrenty.
if not ,try the things art sugested.
if al fails recone it.]
what you need is a rms limiter,it measures/calculates the power long therm ,and limit accordingly.
Judging by their list of covered stuff, i say you are due for a warranty repair. It mentions buzzing with sine signal multiple place, as well as blistered former As covered
Yeah, sounds like a plan. If not, for whatever reason, I'll have chucked quite a bit of cash towards shipping charges. Let's see how it goes *crosses fingers*
I know the 18sw100 is pretty heavy... but surely you can get a reasonable rate?
when I shipped a 3015lf off for repair (in an 18x18x14 box as well), it shipped ups for about 10 dollars (it weighs 9 lbs). should be able to ship the18sw100 for about 25.
when I shipped a 3015lf off for repair (in an 18x18x14 box as well), it shipped ups for about 10 dollars (it weighs 9 lbs). should be able to ship the18sw100 for about 25.
as long as you can see the top plate at the pole piece/gap junction, shouldn't be that difficult to recone it by centering the voice coil over the top plate. I would just worry about getting the proper spider with that silicone addition to it, and using the right adhesive at the spider-to-basket circumference.
"Getting the proper spider"??? I don't know about you guys, but with a speaker of this kind of quality it would be really difficult to maintain this quality piecing together all the individual parts without factory tooling. I wouldn't even TRY to recone a B&C sub without a complete recone kit with the VC, spiders, and cone pre-assembled and properly aligned. Unless of course you are willing to risk having the unit fail again after one teensy mistake that seems insignificant at the time and didn't hurt anything on the last 300W Eminence you did.
Yes that speaker has a special spider in the sense that it is doped with a certain amount of silicone. Its not a typical poly cotton/homes spider. Hence why it is very important. I would not hesitate reconing something like this so long as all the proper parts are included in the kit.
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