Hi friends, I got a pair of old Wharfedale woofers, looks like from w90 vintage speakers, they look like 12". They both rub, one slightly, the other quite a lot. I would like to repair them, but here is the problem. They do not have normal cone, they have foam. This foam is narrow on edges, where it meets surround, and flat accross its thick in the middle, where dust cap would be. They are flat from front. Looks to me like they are solid in the middle, full of foam. So I do not have access to the voice coil to recenter it. Normally I would remove dust cap, put some centering rings in voice coil, loosen and reglue the surround to maintain the centered position. Here, however, no access to voice coil.
Any idea what to do?
Thanks in advance for suggestions.
Ed
Any idea what to do?
Thanks in advance for suggestions.
Ed
Wharfedale used a 0.125'' thick annulus cut from a flat sheet of foam plastic.The shaping that is described is the result of compression at the outer edge and the effects of the adhesive holding the foam to the cone periphery.To remove the cone from the frame requires the use of acetone on the cloth spider and dust dome (it normally requires repeated applications). All the old foam can be removed afterwards. A new foam ring can be made from polyether or polyester foam material.If you have a compass set that uses an ink nib attachment such as the 'Staedtler'ones,then this helps to make a replica of an original surround.The re assembly is then straightforward. Precautions apply ,the cone should be checked for trueness,i.e. it is circular and flat at the rim and should not have creases between the bakelised section and the circumferential ribs.
Sorry I misread adason,s post.On re- interpreting what is described ,I believe it is the later W12/RS/PST model that is being discussed.This is a version of the W12/RS that added an expanded polystyrene foam bung to provide an acoustic filter to enable the speaker to be used in slimline cabinets.Two versions were made,the most common type used a single layer and a second type with two layers that allowed the frequency response to be maintained to a higher point.
Hi VaNarn, thanks for reply. Its definitely later, the one with polystyrene disk glued to the cone.
I have had partial success. I cut the disk out with thin filleting knife, which gave me access to dust cap, and thus voice coil. In one case voice coil was completely destroyed, in other I was able to recenter it. So one works reasonably well.
Btw, these woofers are with massive AlNiCo magnets, so the cabinet must be deep.
I got one mid and tweeter, so I may be able to make one complete speaker out of it.
The midrange is spectacular, with its oversized magnet. And it sounds good too.
Tweeter is nothing special, it pretends to be horn, but in reality its small cone speaker with wave guide infront of its aluminium dustcap.
I have had partial success. I cut the disk out with thin filleting knife, which gave me access to dust cap, and thus voice coil. In one case voice coil was completely destroyed, in other I was able to recenter it. So one works reasonably well.
Btw, these woofers are with massive AlNiCo magnets, so the cabinet must be deep.
I got one mid and tweeter, so I may be able to make one complete speaker out of it.
The midrange is spectacular, with its oversized magnet. And it sounds good too.
Tweeter is nothing special, it pretends to be horn, but in reality its small cone speaker with wave guide infront of its aluminium dustcap.
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