Anyway to fix a speaker with Voice coil rub?

[Low_fidelity2100]

One of the Cerwin Vega ER123's in my 412 has developed a voice coil rub... Luckily we don't have any shows booked until the 30th, so I got awhile to sort this out...But is there any way to fix a speaker with voice coil rub? Or is it sorta gone?

I'm basically poor so if theres any sorta DIY stuff I can do, I'd love to hear it. I'm guessing theres nothing I can do, but never know til ya ask...I don't really have any money to speak of, so replacing it (with anything really) is sorta a long shot for me...or would require me to sell some stuff. So any idea's are welcomed.
I also really don't wanna just let the speaker go if anything can be done, those ER123's are really hard to find (totally regretting selling the other two that were originally in the cab). An I hear the weber copies aren't dead on.

Any idea's?

 

[ksmith63]

Re: Anyway to fix a speaker with Voice coil rub?

Maybe.

1. Take the speaker out of the box.

2. Press very gently on the cone to find where the voice coil rubs. You want to go about half way between the dust cap and the frame, only pressing down on part of the cone. It should be pretty obvious where the problem is.

3. Get some fingernail polish or heavy glue and apply a small band on the back of the cone (front works too but just looks ugly). The glue band should be 180 degrees from where the coil rubs. You are essentially adding weight to the OPPOSITE end of the cone to try to balance out the movement.

4. Go back to step 2 and repeat if necessary. It may take a little amount of glue or more than you would think.

Hope that makes sense. I worked in a speaker plant for some time and had to do this many many times for prototype builds.

 

[Low_fidelity2100]

Re: Anyway to fix a speaker with Voice coil rub?

Maybe.

1. Take the speaker out of the box.

2. Press very gently on the cone to find where the voice coil rubs. You want to go about half way between the dust cap and the frame, only pressing down on part of the cone. It should be pretty obvious where the problem is.

3. Get some fingernail polish or heavy glue and apply a small band on the back of the cone (front works too but just looks ugly). The glue band should be 180 degrees from where the coil rubs. You are essentially adding weight to the OPPOSITE end of the cone to try to balance out the movement.

4. Go back to step 2 and repeat if necessary. It may take a little amount of glue or more than you would think.

Hope that makes sense. I worked in a speaker plant for some time and had to do this many many times for prototype builds.

Hmm, ok...From pressing on the cone it seems like the rub is coming in when the cone is depressed relatively deeply, and seems to be happening no matter where I press around the cone (i.e. the same at 12 o'clock as at 3 and 6 and 9, etc)...But again always when pressed in deepish (ya know, deep for a speaker at least). So what would you suggest in that case? Someone on a different forum suggested rotating the speaker 180 degree's to counter balance it or something, Would that work in this situation, being as it seems to be persistent all the way around?

Also, in case this matters....Pressing on it the rub sounds alot more noticeable than it does when actually playing through the speaker at volume. But the rub is noticeable when playing loud or quiet doesn't seem to get louder with the volume of the amp. The rub also isn't always there, 5 times outta 10 its there when I press on the cone, and only seems to present itself when playing extremely clean (though I'm guessing its just not noticeable with dirt)....Oh and lastly, in inspecting the speaker theres two spots on the surround where it looks like there was a crack in the surround and someone repaired it with something (looks shiny like nail polish or clear paint or something), dunno if that changes anything?

 

[ksmith63]

Re: Anyway to fix a speaker with Voice coil rub?

Hmm, ok...From pressing on the cone it seems like the rub is coming in when the cone is depressed relatively deeply, and seems to be happening no matter where I press around the cone (i.e. the same at 12 o'clock as at 3 and 6 and 9, etc)...But again always when pressed in deepish (ya know, deep for a speaker at least). So what would you suggest in that case? Someone on a different forum suggested rotating the speaker 180 degree's to counter balance it or something, Would that work in this situation, being as it seems to be persistent all the way around?

Also, in case this matters....Pressing on it the rub sounds alot more noticeable than it does when actually playing through the speaker at volume. But the rub is noticeable when playing loud or quiet doesn't seem to get louder with the volume of the amp. The rub also isn't always there, 5 times outta 10 its there when I press on the cone, and only seems to present itself when playing extremely clean (though I'm guessing its just not noticeable with dirt)....Oh and lastly, in inspecting the speaker theres two spots on the surround where it looks like there was a crack in the surround and someone repaired it with something (looks shiny like nail polish or clear paint or something), dunno if that changes anything?

Rotating the speaker probably won't do anything. Essentially it is a non-permanent version of adding weight to the cone (my first reply).

Pressing the cone down will make the rub very noticeable because you don't have the sound to cover it up.

How deep are you pressing on the cone to make it rub? I recommend to keep trying my first reply but don't move the cone as deep. Thin cones bend easily so you may be bending it just enough to force a rub that isn't really there. Hopefully you can find where it starts to rub and make it a little bit better....just enough so you don't hear the rub when you play.

 

[zzmoore]

Re: Anyway to fix a speaker with Voice coil rub?

It is not uncommon for mounted speakers to develop coil rub. As you have already been advised, try rotating the offending speaker 180 degrees. It is not a magic wand or a cure-all, but you would be surprised how often the change in gravity will fix coil rub in a mounted speaker.....
Good Luck

 

[post toastie]

Re: Anyway to fix a speaker with Voice coil rub?

what exactly is a voice coil rub ?

i have a rattle or buzz (not sure which) on my Peavey Basic 50 (bass amp) which i thought was a loose speaker, but since it appears to be clamped tightly...i am wondering it may be a voice coil rub.

thanks.

 

[Low_fidelity2100]

Re: Anyway to fix a speaker with Voice coil rub?

Rotating the speaker probably won't do anything. Essentially it is a non-permanent version of adding weight to the cone (my first reply).

Pressing the cone down will make the rub very noticeable because you don't have the sound to cover it up.

How deep are you pressing on the cone to make it rub? I recommend to keep trying my first reply but don't move the cone as deep. Thin cones bend easily so you may be bending it just enough to force a rub that isn't really there. Hopefully you can find where it starts to rub and make it a little bit better....just enough so you don't hear the rub when you play.

Pressing it relatively deepish to get the rub, but I can hear it (as a static under the guitar) when playing. Its barely noticeable, and only on low notes, but its there. I'll try like ya said pressing less deep, hopefully find the spot where it starts showing.

It is not uncommon for mounted speakers to develop coil rub. As you have already been advised, try rotating the offending speaker 180 degrees. It is not a magic wand or a cure-all, but you would be surprised how often the change in gravity will fix coil rub in a mounted speaker.....
Good Luck

Yeah i tried rotating the speaker 180 degree's it didn't seem to make any difference really. Still a slightly static under deep clean notes.

what exactly is a voice coil rub ?

i have a rattle or buzz (not sure which) on my Peavey Basic 50 (bass amp) which i thought was a loose speaker, but since it appears to be clamped tightly...i am wondering it may be a voice coil rub.

thanks.

It sounds like static under the sound of the guitar.

You should check all the screws on yer amp. Anything that can be tightened, tighten it, and make sure the rattle/buzz isn't coming from somewhere else...could even be a loose connection in the output jack of the guitar, or a dry solder joint in the amp rattling when theres signal. If ya wanna check if its electrical, with the volume turned up, but the guitar volume turned down, Bang yer fist on the top of the amp. If its a loose component, it'll present itself when you bang on the amp. If not, then its just a loose screw or three rattling something.

 

[post toastie]

Re: Anyway to fix a speaker with Voice coil rub?

It sounds like static under the sound of the guitar.

You should check all the screws on yer amp. Anything that can be tightened, tighten it, and make sure the rattle/buzz isn't coming from somewhere else...could even be a loose connection in the output jack of the guitar, or a dry solder joint in the amp rattling when theres signal. If ya wanna check if its electrical, with the volume turned up, but the guitar volume turned down, Bang yer fist on the top of the amp. If its a loose component, it'll present itself when you bang on the amp. If not, then its just a loose screw or three rattling something.

thank you, Low_fidelity2100. will do.