Wharfedale 11.0 buzz

[GoldenGord]

Hi all,
I bought these Wharfedale 11.0 secondhand and they were great for a week and all of a sudden one speaker made a buzzing sound. First mistake I made, at least I think it's a mistake, is that I forgot to put rubber pads beneath the speakers when they were in the tv cabinet.

I tried to see if it was the wires that were messed up and while switching them up between the two speakers, at one point the issue seemed to be resolved. I wanted to tighten the wires but then the buzzing sound returned and no matter how many times I switched the cables, it would not go away.

The buzzing sound can be heard at low frequencies. I used an app to produce a 100 Hz tone and used another one to measure the sound. You can see that the normal speaker has a slight peak at 100 Hz and the rest is quite ok. The malfunctioning speaker has all kinds of noise/peaks at higher frequencies. Which can also be heard in the video I made (I didn't have the app yet, so it's music).
https://www.youtube.com/shorts/8iScYwNots8?feature=share


So I opened up the speaker (which took me a while to figure out..) and tried to find a cause to this buzzing sound. I found that the rubbery glue(?) that holds the tinsel leads is torn off on the speaker that malfunctions. Holding the wires while the speaker is on doesn't help to get rid of the buzz, so they're not creating this sound. Could it be the rubber/glue? What else could it be? I compared it to the woofer of the working speaker and that was the only difference I could find. Is it possible to fix this or is it beyond repair?
If it is the glue, could I just fix it using a glue gun?

The woofer is out of the speaker box, so it's nothing in the speaker box that's causing this buzzing sound.

 

[Binkman]

Welcome to A.K.
Hard to say. Got a pic of the front face?

 

[GoldenGord]

Thank you!
Here's a pic of the front face.

Front face diamond 11.0

• GoldenGord
• Jul 10, 2022

 

[cademan]

Is the voice coil rubbing on the magnet somehow?

 

[GoldenGord]

Is the voice coil rubbing on the magnet somehow?

Any idea how I can verify that?

While looking for some more info on voice coils, I found this info:

Glue Failure of Voice Coil Attachments - For a host of reasons, glue attachment of the voice coil to the cone or spider may fail. The immediate result of even a partial failure is the voice coil is no longer precisely centred.

An off-centre voice coil will scrape against the pole pieces and this soon damages the wire it is wound from, possibly creating shorted turns in the process. This highly audible defect is called 'poling' by repairers. Broken or cracked attachments vibrate severely under normal drive forces, so this is also highly audible as buzzing noise or distortion. Repair is sometimes possible but re-coning or replacement is often needed.

Based on the info I gave, do you think this might be the issue?

 

[cademan]

With both thumbs, gently push down on both opposite sides with equal force on the cone and if there is a problem, usually you can physically feel the voice coil rubbing on the magnet.

A speaker that is in good working order will be as smooth as a baby's butt.

 

[GoldenGord]

With both thumbs, gently push down on both opposite sides with equal force on the cone and if there is a problem, usually you can physically feel the voice coil rubbing on the magnet.

A speaker that is in good working order will be as smooth as a baby's butt.

You're right, I can feel and hear some friction when I move the cone down with my thumbs, especially when I compare it to the functioning speaker.
So it may be the voice coil... how repairable is that?

By the way, just wondering, does this really happen all of a sudden to a woofer or do you think the guy that sold it might have done something to temporary fix it and sold it to me?

 

[cademan]

This usually happens when speakers experience too much current or the more common effect of overdriving it into clipping and distortion for long periods of time.

It can also happen when an amp experiences an event such as a short in the output stage when the particular amp has no speaker protection circuitry and sends direct current or DC through the voice coil. DC causes the voice coil to heat up abnormally and burn or fuse the turns of wire together thus causing melted particles or the copper wire itself to rub against the magnet. Basically, burnt wire is rubbing against the magnet.

In extreme circumstances, the voice coil gets fried and the speaker is blown and is no good. The only way to fix it is to either recone the existing speaker or just simply replace it.

In moderate circumstances, the speaker gets abused and maybe one or two turns of wire short from hard clipping but the speaker still functions. The previous owner may have abused it in this way.

 

[GoldenGord]

This usually happens when speakers experience too much current or the more common effect of overdriving it into clipping and distortion for long periods of time.

It can also happen when an amp experiences an event such as a short in the output stage when the particular amp has no speaker protection circuitry and sends direct current or DC through the voice coil. DC causes the voice coil to heat up abnormally and burn or fuse the turns of wire together thus causing melted particles or the copper wire itself to rub against the magnet. Basically, burnt wire is rubbing against the magnet.

In extreme circumstances, the voice coil gets fried and the speaker is blown and is no good. The only way to fix it is to either recone the existing speaker or just simply replace it.

In moderate circumstances, the speaker gets abused and maybe one or two turns of wire short from hard clipping but the speaker still functions. The previous owner may have abused it in this way.

Thanks for your replies!
What I don't understand is how reconing the speaker helps the voice coil issue. If the voice coil is burnt, shouldn't that be replaced? Or is that part of reconing the speaker?

And I guess the next step is to remove the cone and see what's underneath, since it can't be fixed without destroying the speaker any further.

 

[cademan]

Thanks for your replies!
What I don't understand is how reconing the speaker helps the voice coil issue. If the voice coil is burnt, shouldn't that be replaced? Or is that part of reconing the speaker?

When you buy the parts to recone a speaker, you get the cone itself, the spider, and a new voice coil all attached to the new cone. Look up on how to recone a speaker. It will show you everything you need to know.

 

[cademan]

And I guess the next step is to remove the cone and see what's underneath, since it can't be fixed without destroying the speaker any further.

If you can find another exact replacement speaker, or find a recone kit for that specific brand and model speaker then there is no need for the old original speaker and you will have to destroy it to see the coil and maybe see what damage was done.

 

[cademan]

Look up or google "speaker recone kits". You will get all the info you will ever need.

 

[GoldenGord]

Look up or google "speaker recone kits". You will get all the info you will ever need.

These recone kits are more expensive than what I paid for these speakers (70 euros). Moreover, there are not many Wharfedale kits, let alone 11.0. Will keep in mind to not buy Wharfedale anymore.. quite obscure speakers, while they do have a good reputation. And another reason not to buy Wharfedale: when I contacted them for info on how to get the woofer out, they said they didn't know and instead offered me the diamond 12.0 at a "sharp" price...

I think I'll just try and see if I can swap my diamond 7.1 woofer in the diamond 11.0 speaker box.

I will still open up the cone, just out of curiosity to see what it looks like.

 

[GoldenGord]

Okay, so I took apart the woofer, since it's broken anyways and I was curious to see what could be the cause. Here's the voice coil. It seems intact, or not? Based on images on google, this one seems fine.
But the plastic (?) that was attached to the dome of the voice coil was crunchy though.
I think the voicecoil was in some way loose and that's why it produced that sound.