abnormalcat
New Member
Hello friends! First post here and relatively new to the whole audio scene so apologies in advance if I use some wrong terminology. I need some advice on how to center up the cone/voice coil on a Vifa C20WG-09 that just won't play nice for me.
The beginnings: I recently picked up a pair of DALI IV's off Craigslist. Bought them from an older gentleman who said they were his sister's, until they started sounding weird so she replaced them and pawned them off on him to sit in his garage for several years. All four of the woofer surrounds were completely disintegrated - probably why they sounded funny. Time for my first refoam!
The refoaming: After removing the woofers from the chassis (Why did DALI have to glue them in?) and ordering some parts, I cleaned off what remained of the old foam and glue, cut open the dust caps, and shimmed the things up with some notebook paper. I have pictures attached. This worked a treat, three of the woofers are perfectly centered. No rubbing, no friction, no issues. Two of them are back in the cabinet and sound great! The fourth woofer is a headache though.
The problem child: I've glued this particular one together, and subsequently unglued it, three times now. The first time I started out like all the others. four shim locations, using two strips of notebook paper at each location. I glued the surround to the cone first, making sure it was as centered as I could get it, let it dry for a day, then glued it to the basket. After my glue had set I took the shims out and the cone moved to one side, meaning it now rubbed in the center. Luckily the glue wasn't hardened yet so it was relatively easy to clean it off and try again. This time I stacked three strips of notebook paper for my shims but the same thing happened upon removal. On my final attempt, I marked the location the voice coil was rubbing and stacked as much notebook paper in that space as I could (3 strips) with only 1 strip in the other locations, and shifted the surround towards that side as I glued it, hoping it would pull enough to keep everything centered. No dice. Something seems warped, or saggy, to the point that simply pulling one way or the other on the cone or surround, such as moving the location of the surround on the basket would pull, won't center up the voice coil. Instead, a kind of "twisting" pressure is needed, where one side of the cone needs to be pushed up while the other is pressed down. That's not the kind of motion I can achieve by adjusting where on the basket I glue the surround. I hope I've described this well enough y'all can understand the issue.
So my question is: how can I get this to center up nicely? While new a this, by base technique seems sound - three of the four woofers turned out well. Shims for the win! The nuclear option would be to recone the sucker, but I'd like to avoid that if possible. My theory is that the original surround was damaged so long ago and likely used while damaged, that something has warped, either through time or heat. I've attached (hopefully ) some pictures of the woofer in question (and some before/after shots of the successfully repaired woofers), I can post more if there are other angles that would be helpful. Thanks in advance for your help/advice!
The beginnings: I recently picked up a pair of DALI IV's off Craigslist. Bought them from an older gentleman who said they were his sister's, until they started sounding weird so she replaced them and pawned them off on him to sit in his garage for several years. All four of the woofer surrounds were completely disintegrated - probably why they sounded funny. Time for my first refoam!
The refoaming: After removing the woofers from the chassis (Why did DALI have to glue them in?) and ordering some parts, I cleaned off what remained of the old foam and glue, cut open the dust caps, and shimmed the things up with some notebook paper. I have pictures attached. This worked a treat, three of the woofers are perfectly centered. No rubbing, no friction, no issues. Two of them are back in the cabinet and sound great! The fourth woofer is a headache though.
The problem child: I've glued this particular one together, and subsequently unglued it, three times now. The first time I started out like all the others. four shim locations, using two strips of notebook paper at each location. I glued the surround to the cone first, making sure it was as centered as I could get it, let it dry for a day, then glued it to the basket. After my glue had set I took the shims out and the cone moved to one side, meaning it now rubbed in the center. Luckily the glue wasn't hardened yet so it was relatively easy to clean it off and try again. This time I stacked three strips of notebook paper for my shims but the same thing happened upon removal. On my final attempt, I marked the location the voice coil was rubbing and stacked as much notebook paper in that space as I could (3 strips) with only 1 strip in the other locations, and shifted the surround towards that side as I glued it, hoping it would pull enough to keep everything centered. No dice. Something seems warped, or saggy, to the point that simply pulling one way or the other on the cone or surround, such as moving the location of the surround on the basket would pull, won't center up the voice coil. Instead, a kind of "twisting" pressure is needed, where one side of the cone needs to be pushed up while the other is pressed down. That's not the kind of motion I can achieve by adjusting where on the basket I glue the surround. I hope I've described this well enough y'all can understand the issue.
So my question is: how can I get this to center up nicely? While new a this, by base technique seems sound - three of the four woofers turned out well. Shims for the win! The nuclear option would be to recone the sucker, but I'd like to avoid that if possible. My theory is that the original surround was damaged so long ago and likely used while damaged, that something has warped, either through time or heat. I've attached (hopefully ) some pictures of the woofer in question (and some before/after shots of the successfully repaired woofers), I can post more if there are other angles that would be helpful. Thanks in advance for your help/advice!
, I tried it with a AAA batter I had lying around. While it looks centered, I could hear and feel that it was rubbing. I also noticed that the spider raised in a non-uniform way. Thanks for the lead on replacing spiders, hopefully it doesn't come to that!
