Speaker Pebble

[Michael Bright]

Hi all!
I've got a GK Neo 412 with one problem speaker - there's something stuck between the diaphragm and the dust cover, not 100% sure what it is (maybe an internal solder that's come loose?). Anyone else had a similar issue with a speaker before? Would making a small hole in the dust cover be the worst idea possible? Might be a bit like trying to get a pick out of an acoustic...just didn't know how much the dust cover affects the integrity of the speaker. Any advice would be appreciated!

Mike

 

[mmbongo]

Compromising the dustcap would basically ruin the speaker. It's there for many reasons. But as long as you replace it, it would be okay. GK would probably send you one.

Now I'm not saying you should do this, I'm just telling you what I've done many times in the past to replace dust caps...I would just slice them off with a razor, leaving a half inch or so intact (the part glued to the cone plus a little more..basically slicing in a circle). As long as you have the indentical dustcap to replace it with and the proper glue you can just glue it back on. Leaving some of the old dustcap gives you a good surface to glue to.

Now I know those driver have a vented pole piece (one big reason why you want the dustcap sealed) but I don't remember if they are screened. If there is no screen, whatever it is in there should fall out through the vent if you can get it lined up.

 

[Redbrangus]

Have you confirmed that the tensile leads between the terminals and the voice coil are not touching the cone in the back?

 

[Redbrangus]

The reason I ask about the leads is that I'm thinking that you want to be certain of your diagnosis before performing radical surgery. If what you suspect is correct, you ought to be able to hear the foreign object rattling around on the back of the dust cap when you point the speaker downward and rock it back and forth or shake it.

I'm not exactly the ultimate authority, but IMO the dust cap isn't absolutely integral to the operation of a loudspeaker. I've used speakers for long periods of time without dust caps with no apparent harm. The dust cap IS integral to keeping foreign matter out of the speaker's magnetic gap though, so it's definitely not a recommended practice. @mmbongo's description and advice are well-considered, including trying to get the intruder to fall out of the back if there isn't a screen that would stop it...that really would be like trying to shake a pick out of an acoustic guitar, if not harder, but it would be worth a try before excising the dust cap.

Another potential source of annoying vibrational noise is small failure of the adhesive between the cone and the surround, or where the cone and the dust cap are joined. I've had some very loud, annoying buzzes occur under circumstances like that.

 

[byacey]

Sometimes a little piece of glue can break off and rattle inside. You can remove and reuse the dustcap if you use an exacto knife and carefully cut around the perimeter of the dustcap.

With the flat of the blade held parallel to the angled cone to prevent slicing into the underlying cone, make very shallow cuts just inside the glue line to avoid slicing into the coil leads that may potentially be close to the underside of the dustcap.

After cleaning loose debris out, reglue the cap with speaker glue rubber cement.

 

[Michael Bright]

Right on, thanks everyone. It's definitely something inside instead of the cap itself being loose anywhere or the leads hitting the back of the cone. I may one day get brave enough to try and cut the dust cap off for reuse. But, for now, i'll live with it a bit longer and keep my eyes peeled for another speaker. Thanks again!

 

[Redbrangus]

A pro re-coner might help you out for a minimal cost. At any rate, good luck with it.

 

[Coolhandjjl]

Dustcaps are absolutely important to the speaker. The diameter, depth, etc, are all calculated so the waves of various frequencies leave the cone properly. Take a look at some Google pics. Some seem flat-ish like a saucer, some seem almost like 1/2 a tennis ball. Again, the specific shape is calculated so the driver performs across its designed frequency range properly.

 

[mmbongo]

Dustcaps are absolutely important to the speaker. The diameter, depth, etc, are all calculated so the waves of various frequencies leave the cone properly. Take a look at some Google pics. Some seem flat-ish like a saucer, some seem almost like 1/2 a tennis ball. Again, the specific shape is calculated so the driver performs across its designed frequency range properly.

Yep. The dustcap is absolutely integral to the speaker. Using a speaker without a dustcap is kinda like removing the tires from your car and running on the bare rims. Sure, it will still roll and may even get you where you're going...but it doesn't work right and will eventually damage something.