Subwoofer repair

[Jerrold Stoke]

Hello. After many years of service , my home theater sub. started to distort at only the lowest of frequencies. I have inspected the cone and was expecting to see some damage ,but none visible .What other kind of damage should I look for?

 

[TLS Guy]

Hello. After many years of service , my home theater sub. started to distort at only the lowest of frequencies. I have inspected the cone and was expecting to see some damage ,but none visible .What other kind of damage should I look for?

You have not given much information, and we have no idea which sub. It is hard to know if it a driver problem or an amp problem. Without test gear I doubt you can solve it.

My first guess is that there is a voice coil issue with the driver, like the start of cone voice coil separation or a dropped wire turn or two on the Voice coil.

Either was this is probably not a solvable problem if it is an old sub parts are not likely available.

 

[j_garcia]

You can't see a burnt voice coil, but that sounds like what you described as TLS mentioned.

 

[William Lemmerhirt]

Well if it HAS been many years of service, it might be the appropriate time to invest in a modern high quality subwoofer.

 

[Jerrold Stoke]

You have not given much information, and we have no idea which sub. It is hard to know if it a driver problem or an amp problem. Without test gear I doubt you can solve it.

My first guess is that there is a voice coil issue with the driver, like the start of cone voice coil separation or a dropped wire turn or two on the Voice coil.

Either was this is probably not a solvable problem if it is an old sub parts are not likely available.

Thanks for your input .I'm New to this . I will repost with sub make and model.

 

[Eppie]

"Started to distort" does not provide a lot of information so please be as descriptive as you can. There can be noise from the voice coil rubbing against the magnet, or the foam surround on the cone could be damaged or rotten, or the distortion could be from the amplifier which would have a different sound to it. Subwoofers are notoriously difficult to repair as it can be a challenge finding an exact replacement for the driver and the plate amp parts are usually covered in epoxy to prevent vibration.

 

[Jerrold Stoke]

"Started to distort" does not provide a lot of information so please be as descriptive as you can. There can be noise from the voice coil rubbing against the magnet, or the foam surround on the cone could be damaged or rotten, or the distortion could be from the amplifier which would have a different sound to it. Subwoofers are notoriously difficult to repair as it can be a challenge finding an exact replacement for the driver and the plate amp parts are usually covered in epoxy to prevent vibration.

Thanks for your input The cone looks fine . I have upgraded the sub, but just want to see if I could repair the old one. The distortion is like a buzz that I would expect from a damaged cone. I will repost with make and model of sub.

 

[Eppie]

Thanks for your input The cone looks fine . I have upgraded the sub, but just want to see if I could repair the old one. The distortion is like a buzz that I would expect from a damaged cone. I will repost with make and model of sub.

The cone and surround will usually show visible signs of damage if torn so that's easy to spot. If the voice coil is the issue like TLS_Guy suspected, you would need to replace the driver. You should be able to push the cone up and down by hand and not hear or feel the coil rub against the magnet.

 

[William Lemmerhirt]

Has this subwoofer ever made a “clack” sound?

 

[j_garcia]

If it occurs at particular frequencies, which is what it sounds like was described, I would lean toward voice coil.

Visually, if the surround isn't ripped, I would not expect the cone as an issue. I have had drivers with surrounds that had a small tear that wasn't visible until you pushed on it do this though. Is it a foam, paper or rubber surround?

 

[highfigh]

Hello. After many years of service , my home theater sub. started to distort at only the lowest of frequencies. I have inspected the cone and was expecting to see some damage ,but none visible .What other kind of damage should I look for?

It's possible that the spider has separated from the voice coil or frame, the surround may be foam and in that case, it's highly likely that it's falling apart. The foam may be replaceable, though- show the brand and model.

 

[highfigh]

Thanks for your input The cone looks fine . I have upgraded the sub, but just want to see if I could repair the old one. The distortion is like a buzz that I would expect from a damaged cone. I will repost with make and model of sub.

The only sound that a cone might make is if the glue joint in the paper fails- aside from that, it's the voice coil, spider and surround that makes the noises.

Make sure the sound isn't coming from the cabinet. I have heard sounds like this coming from loose components inside, usually on the circuit board of the amplifier.