Speaker making a wierd sound- bad voice coil?

[kwk13]

I have two speakers in a cabinet and when you hit certain notes, I hear this wierd "wooshing" sound in the background. Is that a bad voice coil or something similar? I've tried different amps with the same result. The cabinet itself has stayed the same though. At first I thought it might just be something rattling on the speaker magnet but I don't see anything. Any help would be appreciated.

[deeval]

Disconnect one speaker at a time to see if it does the sound then you can know which speaker is bad.:rolleyes:

[kwk13]

Man, I never thought of that!! :) (trying to be funny)

My question is, based on the horrible description, is that what a bad voice-coil sounds like? How do you know if you fried the voice coil of a speaker?

Thanks Again

[deeval]

Not Funny just the way you asked?
You can pull the speakers and very gently push on the speaker cone just a little slow movement in and out and most of the time you will feel the rubbing on the coil,:crazyguy

[kwk13]

Thanks Deeval. So if the voice coil is bad I will feel the cone rubbing on it? What happens to the voice coil that causes this? Does it fall out of place or something?

[jpfeiff]

I'm have the same issue with a vintage speaker that just re-coned. Bad "wooshing" noise on certain notes....what gives??

[kwk13]

I lightly pressed on the cone and don't hear any scraping sounds and it seems pretty flexible. Does that rule out the voice coil as a problem?

[Southbay Ampworks]

I lightly pressed on the cone and don't hear any scraping sounds and it seems pretty flexible. Does that rule out the voice coil as a problem?

Nope. It could be fine out of the cab, but start to rub as it heats up from being used. In MOST cases it's a good test, but not 100% foolproof. When you can feel the rub out of the cab, then you know it's toast. Time for a recone, or replacement.

[kwk13]

Thanks for the input Southbay! I know you are an expert on speakers, so what would you recommend as my next step? Is it a bad speaker? I'm going to try it in a different cab tonight and see what happens. If it's a bad voice coil, can they be replaced or is it just not worth it?

[bluesjuke]

I'm have the same issue with a vintage speaker that just re-coned. Bad "wooshing" noise on certain notes....what gives??


Can you describe this "wooshing" sound in more detail?

I have a vintage reconed speaker & amp having noise troubles that appear to 'come through' the speaker.
I'm not sure if it's the speaker or an amp problem.
At first I did suspect the coil.

In my example I get noise when the input signal is high (Gibsons) but especially when playing an open low E and a B on the A string played together.
My guitar comes through very clear but I get the noise with it that sounds like circuit problems being heard.through the speaker.

[vibroverbus]

Thanks Deeval. So if the voice coil is bad I will feel the cone rubbing on it? What happens to the voice coil that causes this? Does it fall out of place or something?
the voice coil is wire wound on a tube (the 'former') which is connected to the cone. it moves in and out on a rod (the 'pole piece') with a tiny slot around it (the 'gap').

as you (gently) push the cone in and out, make the pressure as even and centered as possible so you're sure you aren't causing the VC/former to touch the side. then if you DO feel any scratchiness or rubbing then you have a problem.

what causes this can be 1. former warpage from overheating the coil, 2. debris - "crap-in-the-gap", 3. the pole becoming un-centered in the gap, usually from physical abuse.

jpfeiff - if a reconed speaker wasn't done well or carefully evaluated beforehand, it could have problems 2 or 3 despite having a new voice coil (not having problem number 1).

[bluesjuke]

Thanks vibroverbus!
Haven't had the amp very long & am doing other troubleshooting things meanwhile.
I need to do a speaker swap & see if the problem goes away as one step.

[jamison162]

Talk about coming out of the wood work. I just posted this thread
Tuesday. http://www.thegearpage.net/board/showthread.php?t=244038

What's the amp? I'm still trouble shooting my issue. Same exact things as some of you have described. I'm hoping mine is just tube related. That's what Ade said in an email (The Designer of the RV50).

I hear it on both speakers independantly.

[bluesjuke]

It's a Tweed Pro amp.

I plugged the output into another amps speaker & didn't hear it but was advised in the Amp Technical section tht that may be due to the speaker being in a different cabinet than the amp so the tubes were not getting the vibration that could stimulate microphonics.

Swapping out some preamp tubes quieted it down quite a bit but it was still there.
I also noticed that the problem does not appear until after a few minutes of playing.
The only thing I haven't done yet tube wise is swapping out the power tubes.
I did also try swapping the rectifier tube & that made no difference at all.