Broken Subwoofer... DIY Fix or Trash? - AVS Forum
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post #1 of 4 Old 09-24-2012, 07:32 PM - Thread Starter
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My friend gave me a Boston Acoustics VR500 (10") subwoofer that seems to have an issue. I'm not sure if it's worth fixing or if I should just trash it. The subwoofer is for my 7 year old daughter's room, so I'm not looking to spend a lot on fixing it. When I play a test tone through the receiver, the subwoofer makes a distorted crackling sound. I tried it on two different Denon receivers and it does the same thing. I don't think it's a grounding issue, as I connected another subwoofer to both receivers and it sounds fine.

I don't have any DIY experience with speakers or subs, so I'm not sure what I should be looking to replace. I looked at the cone itself and there doesn't seem to be any damage. I'm planning on unscrewing the speaker to see if there is something else I'm missing. Any ideas?

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post #2 of 4 Old 09-25-2012, 07:01 AM
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I would pull the driver and try on a different amp. One of the channels on your receiver would suffice. If it doesn't crackle, it's the amp in the sub. If the driver is good, put it to use as a DIY sub for your PC, bedroom, or even a small HT.
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post #3 of 4 Old 09-25-2012, 08:09 AM
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Quote:
Originally Posted by tokerblue View Post

...When I play a test tone through the receiver, the subwoofer makes a distorted crackling sound....

Push the cone in (and pull out if out of the box) and listen for any sound, like the voice coil rubbing. If the cone's quiet through the middle of the excursion range, and an ohm meter measures a few ohms, the driver's probably good.

Next, verify that you've got proper input voltage match to the input sensitivity. Line level sub out to a line level input, typically RCA jacks. With any sort of subwoofer crossover in place, anything you'd describe as crackling is high-order distortion, potentially from a bad amp, or an overdriven amp. If the drive voltages are ~0.2v (as opposed to 1v), it's likely a bad amp. Lots of choices for a replacement...
http://www.parts-express.com/cat/subwoofer-plate-amplifiers/332?sort=pasc

Have fun,
frank
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post #4 of 4 Old 09-25-2012, 07:21 PM - Thread Starter
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Thanks for the help. Looks like it's a bad amp. Unfortunately, it's probably not worth fixing since I can probably get a used subwoofer for around the same price...
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