PSW50 driver problem (RM3300)
rayski57
Posts: 3
Hi,
some months (12-18) back under certain circumstances we started to note that the sub was buzzing & popping ocassionally.
As it was deemed intermittent and the cause not readily diagnosed (I tested for vc rubbing etc.) we let it ride as it's almost constantly in use with our HT. This week I had the opportunity to pick up a cheap powered sub as a standby and swapped them over.
Upon removing the driver all seemed as it should, nothing visibly or measurably out. Tried swapping in one of my Nakamichi subs to confirm amp is fine and yes, it's not the amp.
The plot thickens, in an attempt to understand the cause I manually deflected the driver cone forward to emulate the movement that produces the unwanted sounds.
Voila, the red/brown membrane that connects the bottom of the driver cone to the frame has come away (glue given up) from about 3/4 of the frame. At higher levels or during more robust bass passages this causes the cone to skew to one side and emit the scratching sound. As the resistance provided is also lower than by design it causes popping when the cone is further extended giving a bottoming out sound.
My question (yes finally he gets there) is what do I use to re-attach this membrane to the frame so that I can return this otherwise perfectly serviceable driver to it's normal behaviour and we can again enjoy listening to our Polk surround system?
some months (12-18) back under certain circumstances we started to note that the sub was buzzing & popping ocassionally.
As it was deemed intermittent and the cause not readily diagnosed (I tested for vc rubbing etc.) we let it ride as it's almost constantly in use with our HT. This week I had the opportunity to pick up a cheap powered sub as a standby and swapped them over.
Upon removing the driver all seemed as it should, nothing visibly or measurably out. Tried swapping in one of my Nakamichi subs to confirm amp is fine and yes, it's not the amp.
The plot thickens, in an attempt to understand the cause I manually deflected the driver cone forward to emulate the movement that produces the unwanted sounds.
Voila, the red/brown membrane that connects the bottom of the driver cone to the frame has come away (glue given up) from about 3/4 of the frame. At higher levels or during more robust bass passages this causes the cone to skew to one side and emit the scratching sound. As the resistance provided is also lower than by design it causes popping when the cone is further extended giving a bottoming out sound.
My question (yes finally he gets there) is what do I use to re-attach this membrane to the frame so that I can return this otherwise perfectly serviceable driver to it's normal behaviour and we can again enjoy listening to our Polk surround system?
Post edited by rayski57 on
Comments
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Check online about what type of adhesive manufactures use to adhere spider to the basket, then if you feel confident enough to reglue it your self, but you may encounter the same problem later on if the the enclosure is too small for the power being applied, or if the driver is underdesigned, ya know, to little excursion capabilities, other than that your only other option is to replace driver with a more capable sub of same or close vas, qts, fs but more xmax so it can handle the power without blowing its suspension, because thats what happened, the subs suspension has failed
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Check online about what type of adhesive manufactures use to adhere spider to the basket, then if you feel confident enough to reglue it your self, but you may encounter the same problem later on if the the enclosure is too small for the power being applied, or if the driver is underdesigned, ya know, to little excursion capabilities, other than that your only other option is to replace driver with a more capable sub of same or close vas, qts, fs but more xmax so it can handle the power without blowing its suspension, because thats what happened, the subs suspension has failed
Hi Tonyw,
Thanks for the prompt response.
Yes, I suspected the cause was the use of a driver that's under spec'd for the available power as this unit haasn't been driven hard (never over 50% gain).
I'll see what I can find online as far as glues go. No issue with doing it myself as it seems easier than refoaming edges which I would consider doing if I had to.
I'll see how the revitalised driver works out and if dissatisfied with performance/longevity I'll replace the RM3300 set with some updated kit. -
let us know how it turns out
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Oops, sorry guys got busy and forgot to come back with progress report.
Well I did as Tony suggested and searched the interweb for manufacturer/repairer info on how to re-attach the spider.
I found http://reconingspeakers.com/faq/reconing-faqs/how-to-diy-recone-with-unassembled-parts/ their re-coning instructions are pretty clear. It seems that a contact adhesive (and due care) is needed to re-attach the spider.
Things have been a bit hectic here, but will get to it in the next couple of days and report back on the experience for anyone else suffering the same issue.
Cheers
PS if the job is a success I will probably pension these off into our multi-purppose media room (Music room/games room etc), or just sell off the RM3300 + CS101 to replace with another 5.1/7.1 set.
