Aiwa SX FN520 Woofer Hardened Cloth Surround Restoration

[SpeakerNoob]

Hi AK family,

Wishing everybody happy holidays! I recently got hold of a pair of Sony Aiwa SX FN520's at an auction. I think they are from early 2000. The particle board of both cabinets was almost destroyed and I managed to get the speakers out safely. I will get replica MDF cabinets made to restore them.

However, my issue is with the left woofer. There are some dimples (see attached image) in the cloth surround which do go away despite me pushing them back up with my finger. I have been told that the dimple shouldn't affect the speaker performance or excursion, but I want the surrounds to look aesthetically pleasing.

I've been guided to put DOT 3 brake fluid to restore their suppleness since they have become hard. Is there anything I can do to remove the dimple? I have tried putting a cut power cord of the same diameter on the surround underside (where the spider and cone are) to support the shape, and it does work, but is only limited till I put some pressure on the cord with my thumb. As soon as I remove the cord, or the pressure, that area dimples again.

Will appreciate any help I can get. Cheers!

 

[SpeakerNoob]

Re-uploaded the image if it doesn't show.

 

[vinylkid58]

Those surrounds appear to be foam, not cloth, so definitely DON'T put brake fluid on them, as it could turn them to goo.

I'd be tempted to try applying a bit of heat to try and reshape the surround, but go easy.

jeff

 

[SpeakerNoob]

Those surrounds appear to be foam, not cloth, so definitely DON'T put brake fluid on them, as it could turn them to goo.

I'd be tempted to try applying a bit of heat to try and reshape the surround, but go easy.

jeff

Hey Jeff! I'm tempted to try a bit of heat from a blow dryer but am worried that the surround glue will come off?

Also, I'm sure that they aren't foam. Could be some other material, seems definitely like they are cloth. Uploaded close up pics

 

[vinylkid58]

Up close they do look like some kind of treated cloth. I still wouldn't put any chemicals on them.

jeff

 

[A400]

I'd be tempted to try applying a bit of heat to try and reshape the surround, but go easy.

This is what I'd do, and have done, to repair similar defects.

I'm tempted to try a bit of heat from a blow dryer but am worried that the surround glue will come off?

A hair dryer is exactly what I'd recommend. It's easy to control the heat to ensure you don't overdo it and in many cases there's a cooling mode to firm up the surround in the new shape. It's unlikely the glue will be damaged before you heat the surrounds enough to reset the coating. If it was that hot you'd damage the surround too.

What you need is a form or something to hold the surround in the right shape while you heat it and then while it cools. Once it's cool it should stay in the correct shape, but it might take a couple of attempts.

 

[SpeakerNoob]

Thanks, I think I'll try the hair dryer tomorrow. My main issue is finding something (I don't have foam) that will keep the shape in the cooling period. The power cord (cut from an old electric kettle) is too heavy and won't stay taped to anything to provide it stability, even though it's the perfect shape. Plus, I can't keep the speaker upside down (with the magnets facing up), because there's no clearance to let the surround hang in reverse. The surround gets squished when I reverse it, unlike other speakers where the cone and surround are significantly recessed, allowing for a flat placement without damage.

This is what I'd do, and have done, to repair similar defects.

A hair dryer is exactly what I'd recommend. It's easy to control the heat to ensure you don't overdo it and in many cases there's a cooling mode to firm up the surround in the new shape. It's unlikely the glue will be damaged before you heat the surrounds enough to reset the coating. If it was that hot you'd damage the surround too.

What you need is a form or something to hold the surround in the right shape while you heat it and then while it cools. Once it's cool it should stay in the correct shape, but it might take a couple of attempts.

 

[SpeakerNoob]

Thanks, I think I'll try the hair dryer tomorrow. My main issue is finding something (I don't have foam) that will keep the shape in the cooling period. The power cord (cut from an old electric kettle) is too heavy and won't stay taped to anything to provide it stability, even though it's the perfect shape. Plus, I can't keep the speaker upside down (with the magnets facing up), because there's no clearance to let the surround hang in reverse. The surround gets squished when I reverse it, unlike other speakers where the cone and surround are significantly recessed, allowing for a flat placement without damage.

@vinylkid58 @A400, It worked! A little bit of heat from the hair dryer and the dimpled area on the surround softened up. I used the same power cord and foam bits to keep it in place when the cloth was cooling down and it kept its shape. Man, I am so happy I could retain the cloth surrounds. Thank you! Check out the snaps

Also, I have a few more questions regarding the speakers. Since I'm building the cabinets again with MDF, I wanted to know if it's possible to add an active crossover plate at the back. I don't want to use a pre-amp to power these speakers. So, for the drivers, I'm sharing e-bay links for your reference. In one speaker cabinet, there was one Aiwa 6" Woofer, and three more speakers, which provide 3 way front surround sound. The drivers are two mids and one small tweeter (no brand so I'll ignore). This is the first Aiwa 3" Midrange Speaker and this is the second Aiwa 3" Midrange speaker. Btw, the OEM speakers have a very small cross-over which I can't make sense of

Now for the big question—Is there anyway that I could build an active crossover board for this driver setup? I'm very new to this, but I think having them powered via an active Lepai plate might work better? Do I need a cross-over board in conjunction with this plate? I am unable to calculate the ohms and total power output per cabinet. In my mind, I would put two of the Lepai plates with 4 drivers each, per cabinet.

Will appreciate any guidance and help. Thanks!