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GENERAL speaker repair question

S

Spanky123

Jul 22, 2010
182
36
#1
On my new amp, I am getting a lot of hum on the low notes, causing me at first to believe that I blew a speaker. I examined the speaker carefully for the first time today and I can see that the material on the outer rim of the speaker is loose over about 30% of the perimeter. This material is made of a dense foam (I don't know what it is called). It encircles the speaker and has indentures where the screws go.

I can see that the rest of the material is glued down or otherwise secured over the rest of the speaker. I don't live near a service center and I am wondering if I can perform the fix myself. I have Elmer's and epoxy. Should I attempt to glue it myself? On further inspection it does not appear to be the source of the hum, but I think it should be glued anyway.

General information appreciated.
 
#2
I doubt it's the source of the problem. Personally I wouldn't bother with it right now. If it makes you feel better, go ahead and glue it.

With your head next to the speaker, gently push the woofer in and out. Do you hear any sort of a grinding sound?
 
#3
Hi.

The "hum" is probably air going back and forth through the opening.

30% is IME too much to be "just glued back", the voice coil is going to be out of alignment almost certainly.

If You want to try DIY way, there's nothing you can do to make the matters worse, but there's a few things you can do to increase the odds of a success.

First IMHO is to dump both the Elmers glue and epoxy idea, and use an adhesive more suitable for speaker repair.
I've used silicone based adhesives of various brands and trade names with sucess.

Second is to align the voice coil before the gluing and keeping it aligned during the curing of the chosen adhesive.
That can be acchieved by carefully removing the dust cap, and using strips of suitable thickness paper between the center pole and the voice coil tube.

I wouldn't do the "scratch test" in this case since there's practically just the spider aligning the VC and it is going to rub, possibly damaging it beyond repair.

In any case:
Good luck.

Regards
Sam
 
#4
Ailene's Super Tack Glue, from Walmart, works fine to glue that surround back. (Some folks believe that's actually what the "official" speaker glue is)

Many people successfully replace the surround without going through the full procedure of removing the dust cone and shimming the voice coil. Since only a portion of the surround has come unglued, I would try merely re-glueing that section back.
 
#6
Hi.

wcriley said:
From the description, I think it's the gasket material that's loose, not the surround.
Click to expand...

Actually, after reading the op more thoroughly I think You're correct.
Reading the sentence right to the end sure has its benefits ;).

If that's the case, just use the Elmers.

Or rip/shave it off like I've done. It serves only a marginal purpose on a front loaded cab.

Edit:I just read the other thread on the subject, and all I can say is to take it to a tech.
Or at least to someone who really can tell what is what.

Regards
Sam
 
#7
Spanky123 said:
On my new amp, I am getting a lot of hum on the low notes, causing me at first to believe that I blew a speaker. I examined the speaker carefully for the first time today and I can see that the material on the outer rim of the speaker is loose over about 30% of the perimeter. This material is made of a dense foam (I don't know what it is called). It encircles the speaker and has indentures where the screws go.

I can see that the rest of the material is glued down or otherwise secured over the rest of the speaker. I don't live near a service center and I am wondering if I can perform the fix myself. I have Elmer's and epoxy. Should I attempt to glue it myself? On further inspection it does not appear to be the source of the hum, but I think it should be glued anyway.

General information appreciated.
Click to expand...

New amp, as in, brand new? Under warranty? Take it in. If it's new to you, can you post a photo of the foam (this is often called the 'surround') and the label or any markings on the frame, so we can see what it is.

Most musical instrument speakers don't have a foam surround, they use a pleated edge with something added to increase durability/change the resonance/compliance/increase damping.

If it's foam and the edge has a semi-circular area between the cone and the frame/cardboard gasket, is this torn or loose where the curve meets the cone or frame? If so, the surround will need to be replaced.

Contact Orange County Speakers or someone else, like Simply Speakers to look for the correct glue for this. You need to make sure the glue won't attack the foam and any solvent-based glue will damage it. Simply Speakers doesn't use/sell PVA (like Elmer's) for attaching the surround, but they use it for coating the outside of it, to make it resist damage from UV, cigarette smoke and just air movement. These three are the main causes of foam surrounds falling apart and if this speaker has spent much time in the sun, you might consider finding a speaker that's more suited to use as a musical instrument speaker.
 
#11
No grinding sound, and the buzz that I have been trying to diagnose goes away when I gently press the woofer. Is that good or bad?

bassgod0dmw said:
I doubt it's the source of the problem. Personally I wouldn't bother with it right now. If it makes you feel better, go ahead and glue it.

With your head next to the speaker, gently push the woofer in and out. Do you hear any sort of a grinding sound?
Click to expand...
 
#13
Spanky123 said:
No grinding sound, and the buzz that I have been trying to diagnose goes away when I gently press the woofer. Is that good or bad?
Click to expand...
"Good" that you found the problem, but the end result is "bad".

If putting pressure on one side of the cone fixes the buzz, then the speaker has been over exerted and the voice coil is out of alignment, the buzzing is the voice coil scraping, and the only cure is to replace the driver (speaker).
Try pressing the cone in around different positions around the outer and inner edge of the cone, see if ther is any scraping at different angles.

I would even remove the speaker from the cab, and do the same pressing outward too.
 
#14
Hi.

Spanky123 said:
the buzz that I have been trying to diagnose goes away when I gently press the woofer. Is that good or bad?
Click to expand...

Depends whether You're able to straighten the basket or not.

IME with a 90% probablity that behaviour indicates a bent basket. A common result of a mishandled speaker.
The rest 10% for out of round voice coil former, detached or deformed spider, deformed cone, etc.

So, good as You have narrowed down the possible causes a bit.

Also kind of bad since:

Given the tolerances Agedhorse gave us in the other thread about the same subject, I find it unlikely that a satisfactory and long lasting straightening method is available for an average DIYer, but once again, it won't hurt any to try.

Regards
Sam
 

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