Dented dust cap?

Dented dust cap?

Postby mijknahs » Wed Sep 25, 2013 3:44 pm

This past Saturday I had a gig and as the sound guy was micing up my cab (using 2 x JBL D120s) he accidentally dented the dust cap with the microphone! I wasn't really pissed (just a bit annoyed) and he said I could use a vacuum cleaner to pop it out (which I already knew) so I told myself to not let it bother me and worry about it the next day.

However, after the gig was over, and I went to look at the dent, and it had popped out by itself during the course of gig! I was pleasantly suprised.
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Re: Dented dust cap?

Postby TI4-1009 » Thu Sep 26, 2013 6:44 am

Ahhh, the classic Steve Parish dent removal technique: CRANK IT!
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Re: Dented dust cap?

Postby NSP » Thu Sep 26, 2013 7:24 am

I had a similar situation happen when we played a block party a few weeks ago. A buddy came up to show me something before our set and knocked the cabinet mic right into the dome of my E120. He felt horrible and I wasn't happy but knew it wouldn't compromise the sound quality. Mine didn't pop out on its own, but a little duct tape pulled it our nicely. I've since purchased grills for both of my cabinets so I don't have to worry anymore. Certainly doesn't look as cool, but it's good peace of mind.
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Re: Dented dust cap?

Postby TI4-1009 » Thu Sep 26, 2013 8:23 am

NSP wrote:I've since purchased grills for both of my cabinets so I don't have to worry anymore. Certainly doesn't look as cool...


Well now, that all depends upon where you get them...

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Re: Dented dust cap?

Postby waldo041 » Thu Sep 26, 2013 8:38 am

I bought some replacement domes the first time my k120 got hit with a mic. I never got around to changing it, and now it has been hit a few more times with NO issues with it's performance. I use duct tape to pull out what I can, masking tape doesn't work that good on the aluminum. Pretty cool Jim popped his out just playing it! Although the domes do have some sound character to the material used, their main job is to keep things out of the voice coil. Dents should not have any alteration to the tone, holes and cracks are where this may become an issue.

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Re: Dented dust cap?

Postby NSP » Thu Sep 26, 2013 10:37 am

TI4-1009 wrote:
NSP wrote:I've since purchased grills for both of my cabinets so I don't have to worry anymore. Certainly doesn't look as cool...


Well now, that all depends upon where you get them...


Ahhh yeah, that is cool. I guess I should have been more specific....I went with the metal waffle style grill for some serious protection. I don't think Courtney could dye those :smile:
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Re: Dented dust cap?

Postby cripeowner » Thu Sep 26, 2013 1:57 pm

I always keep the wood cover on right until I play and even in bewtween sets it goes back on. No one is allowed to walk or hang in my space. I'm kind of a prick about that but I dont care. Too much time effort and money invested to have a stupid mistake happen like tearing the speaker not so much the dust cap.
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Re: Dented dust cap?

Postby kurt eye » Sun Oct 06, 2013 5:37 am

I have a K-120 with a dented dust cap. I have only tested it out hooked up to a stereo at this point, but I noticed some weird buzzing at times. I understand that this is not necessarily a dust cap issue.

I don't doubt those who have experience with JBLs with dented caps who have had no problems, but is it possible that a dented cap can change the pitch slightly sort of like the way a steel drum works?
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Re: Dented dust cap?

Postby Smolder » Sun Oct 06, 2013 7:30 am

kurt eye wrote:I have a K-120 with a dented dust cap. I have only tested it out hooked up to a stereo at this point, but I noticed some weird buzzing at times. I understand that this is not necessarily a dust cap issue.

I don't doubt those who have experience with JBLs with dented caps who have had no problems, but is it possible that a dented cap can change the pitch slightly sort of like the way a steel drum works?


Unless the dust cap is ripped or punctured, it's not likely causing the buzz. I'm told the aluminum does impact the tone of the speaker.

The buzz is typically a misshaped voice coil or dust and dirt particles. The groove and voice coil ribbon have pretty tight tolerances. I have a beautiful orange original paper D120F that I paid a lot for a couple of years ago... about two weeks ago it developed a buzz, but only on a specific note... two weeks later it's got a raspiness across a range... totally unusable. I'm guessing some dust or dirt got inside and is caused the noise... it was a pretty traumatic deal... very bummed. Yesterday, I found a nice and affordable K120 to replace it... but it won't be cheap to re-cone the orange one... and it will never sound exactly the same.
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Re: Dented dust cap?

Postby TI4-1009 » Mon Oct 07, 2013 6:41 am

I've reconed a few stereo speakers. It might be possible to just remove the dust cap and clean out the teeny opening around the voice coil? If that's the problem you might be able to get the dust/dirt out without having to recone? When you recone you usually insert these very thin plastic spacers around the coil so you're sure it's centered before you glue the cone. Gluing a new dust cap on is a piece of cake.
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