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Major Contradiction, Can you replace foam surrounds with Rubber Surrounds on Speakers ???

Hi Guys, I have a major conundrum to decide, and need the experts in the community to help. I have the Wilson Watt Puppy 6's and have 4 woofers that need re-foaming.

 Here's the issue, First, according to Wilson, I had called 2x(at different times) and asked to speak with a speaker engineer, Both times the knowledgeable staff member that answered the phone said that wasn't possible, but would relay any message to them on the spot and get back with me while I hold. My question was: Can you replace the foam surrounds on the Wilson speakers with Rubber Surrounds . After waiting on hold for about 5 minuets, he said "yes, you can",

I Then proceeded to call the well regarded Miller Sound in PA, who is recognized to one of the best in the Industry to do the replacing of speaker surrounds. I proceeded to ask the same question to him, and he said, "No, & that it would change the sound of the speaker and to only redo them using foam surrounds to preserve its original sound quality" . I see no other supporting evidence one way or the other on the net. What do you folks say and please elaborate one way or the other to help me justify my decision. Thank you, Rich
audiofan1
dletch2
455 posts
 
You got some GREAT advise from a professional rebuilder, why are you asking.


You got some generic advice from a rebuilder who probably did not consider how the product was used in application, in your specific model of speaker.  Great rebuilder. I have used them myself a few times. Does not change the validity of the answer. 


When you asked Wilson, did you communicate which model of speakers you were trying to repair and what drivers in that speaker, or was it a totally generic question?  If you asked specifically, then the answer has a lot more merit than generic.


Whatever you change to, it is going to change the sound from home they sound today. Period. 
timlub
2,039 posts
 
I'm an old speaker guy and can tell you that ANY speaker recone is a guess in a sense.  If you have ever re-coned many speakers, you may notice that you get one surround and it is thin and wimpy,  you get another and it is thick and stiff.  Anytime you change the mechanical ease or difficulty that allows the driver to move,  you change QMS.  So the trick would be to try to mimic how stiff that original surround is.  The likely hood is,  If you have a sealed box woofer that you could get away without much noticeable difference using a butyl surround, but be aware,  YES, the woofer spec will change when changing from a foam to rubber surround.  If you do change it, make sure that you re spec the woofer, the port tuning may need to be tweaked.  Again,  if it is sealed, the difference should be minor.  Good Luck,  Tim
erik_squires
16,058 posts
 
I believe, and this is foggy, that the answer is that the majority of the compliance in a driver is the spider on the inside, next to the magnet. The foam or rubber ring we see on the outside is normally the one that contributes the least amount. It's more or less there to keep the cone centered and therefore you can change it quite a bit before having it behave significantly off.


arcticdeth's avatar
arcticdeth
1,572 posts
 
My CV D-9 surrounds are all dry rotted,.....I push the red surround, it just lets my finger push right through, crumbling slightly around my finger.

  My old MTX - AAL 154’s have foam as well, but are still working, no dry rot, no crumbling at all,....still bounce back when slightly pushed into. 
   The old BIC V830 are butyl rubber surround, they are still like new.
      A extremely light finger rub of oil every couple years since the very early 2000’s on the rubber surrounds has worked great, since the first carnation of synthetic oils. The stuff is great. Turntables, any moving part anywhere.


dletch2
455 posts
 

erik_squires10,924 posts04-23-2021 9:28amI believe, and this is foggy, that the answer is that the majority of the compliance in a driver is the spider on the inside, next to the magnet. The foam or rubber ring we see on the outside is normally the one that contributes the least amount. It's more or less there to keep the cone centered and therefore you can change it quite a bit before having it behave significantly off.


Using much more concise language and detail, erik communicated what I tried to above.  At resonance (QMS) for a woofer, the spider, conductivity of the former, etc. are dominant. Push the woofer to the upper end of its frequency range and that changes, and for high frequency drivers, it can be critical across the range. Think of a simple filter. At 1/10 the cutoff frequency of that filter there is no impact. As you approach the cutoff, the impact is noticeable. 


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