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Crackling sound from one speaker at high volume

 

New member
Username: Adidavid85

Post Number: 1
Registered: May-14
Hello all,

I have a B&W XT4 set of speakers and from one of the 2 bass speakers of one cabinet I can hear certain crackling when playing it at relatively high volume for punchy bass sounds. They sound perfect at low and mid volumes. I've tried it with two amps and input sources and the same problem appears.

When pressing on the cone the speaker is completely silent and the surround does not present any cracks.

Anyone has an idea what might be the cause of this?

Thank you very much!
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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 17896
Registered: May-04
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Anyone has an idea what might be the cause of this?



Consistently high(er than appropriate) volume levels. Especially with "punchy bass sounds".


You've probably driven the voice coil out of its linear range more than once. As the coil moves forward it exits the magnetic gap of the motor assembly. The motor no longer has control over the driver and it is driven into an eccentric motion which displaces the voice coil away from its "centered" position. As it begins to move backward it clips the edge of the motor assembly and thus deforms the edge of the coil. When it moves further back it hits the frame of the magnet assembly which further distorts its edge.

The solution is to replace the driver and don't damage the replacement driver by doing the same thing. When you hear distortions, turn down the volume; basic audio rule #1.



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New member
Username: Adidavid85

Post Number: 2
Registered: May-14
Thank you for your reply Jan,

Do you think it is not worth the effort to replace the coil and maybe the spider for this speaker?

Regards,
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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 17899
Registered: May-04
.

Are the drivers still under warranty? If so, then, no, you simply replace the bad driver and it gets sent back to the manufacturer for inspection. Manufacturers use the information they gather in this way to hopefully create more rugged drivers in the future.

What you've done is fairly common so I doubt B&W will find much other than another driver was overdriven by someone wanting more bass than their system could allow. If you've done this rather frequently, you'll often hear a "BLATTT" sort of sound when it first occurs. That's the driver flapping in the breeze while it tries to find center again. That's your cue to turn it down a bit. If this is an AV system, there's several ways to roll off the bass and at times its caused by a crossover filter that is too shallow - something you can't change, only work around. If that's the case, you can set your filter action at a slightly different frequency and see if that changes anything. Since there are few realistic bass sounds in most action movies, you just have to work with the system until you get the bang you want without damaging the driver.
Placing the speaker systems closer to reinforcing surfaces such as walls or the floor will give a natural boost to the bass and allow you to use a different crossover frequency. You really have to just play around with it all.

If this is a driver that is out of warranty, you can get an estimate on repairing the driver. In most cases though, it's easier and in the long run cheaper to just buy a new replacement driver. A speaker repair shop won't typically have parts from B&W and they'll give you generic parts. You could end up with a driver that isn't an equal match to your original.


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New member
Username: Adidavid85

Post Number: 3
Registered: May-14
Thank you very much for the explanation Jan!
The speakers are out warranty but I found a new spare bass speaker to buy so I will go for that.

Cheers,
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