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

If I remember, the woofers on the Watt Puppy's cross over at quite a low frequency (pretty much subs). Changing to rubber is likely to have pretty minimal impact on the performance because of the function of the surround at those frequencies. Keep in mind it was already likely working fairly well with old degraded foam which will be nothing at all like new foam.  Most newer foam is much better with UV inhibitors to reduce degradation if you stick with foam. 

You can't change it. The two materials are completely different.

Surrounds will not appreciably change the sound if they're of the same...or nearly the same geometry and compliance. Foam and butyl are both pretty lossy when it comes to the cone termination. The moving mass difference will likely be not enough to audibly change the sound. When measuring for moving mass half the weight of the spider and surround are subtracted to get to net moving mass.

On big woofers at low frequencies, like in the Watt Puppy, the surround does not appreciably impact the cone movement. Push them to a higher frequency and they will, ditto for mid-woofs at higher frequencies, and mids across most of their frequency range. 

You got some GREAT advise from a professional rebuilder, why are you asking. If you want to go with BR surrounds , go for it. It will change the sound, plain and simple.. It will be what you turn it into.. There is a place for BR, fabric, or silicone surrounds. I have drivers with silks and wire from 1934. They work perfect..

New foams with treatment will last 30 years if you rotate the driver 180 every 2 years or so..

BR 50 years

Fabric, 100 years

Silicone forever... :-)

Regards

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. 

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

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.

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.

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. 

My experience with some Infinity Watkins woofers was that the change was slight and better than old woofer surrounds with holes in them. 

Based on the following link, they’re saying it’s trial and error, and mention things to be aware of.
https://speakerrepairshop.nl/en/questions/foam-or-rubber-surrounds/c-9

My impression is that you want to use rubber surrounds so you won’t have to worry about re-foaming in the future. You’ll still have to replace the diffraction pads at some point, so it’s not going to be completely future proof with rubber surrounds.

You haven’t indicated how long you’ve owned these speakers. Do you have a point of reference to how they use to sound with good surrounds?
I think it’s an important question because if you decide to go rubber how will you know if they sound right? What happens if they come back and you don’t like the way they sound, or you do, but after a couple of years the rubber starts to sag a bit due to weight of driver. How will you know if the rubber surrounds are the proper thinness/thickness for these drivers? You’ll be back to where you are today.

If you do use rubber, and decide in the future to sell the speakers, will you inform any potential buyer you had them re-foamed with rubber instead of foam as they were originally?

My recommendation is to just use foam and not worry about it. Chances are, you’ll sell the speakers before they need to be re-foamed again anyway.

Sure you can. They're yours to do as you please. Is it advisable? Probably not. Its part of the cone's suspension with different properties. Kinda like replacing a Ferrari's suspension. That can be done too. Will it be better? Probably not, especially since the mfg spent time researching the best suspension materials.  I'd stick with the OEM.

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.

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.

<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>

Like I said, Twice NOW. the OP got some great advice from a professional builder.

dletch2, before you make comments MAYBE you should read a tad closer.

If you change the surround it WILL change the driver. There has been a few thread about getting Wilsons refoamed and they didn’t preform correctly. NOT CLOSE.. They were sent in AGAIN and refoamed to correct the issue.

As I recall it was behind not using WILSONs foams, they didn’t even go to different type.. It was the "Wilson" surround that DID make the difference..

Like timlub I’ve done a slough of VC/Cone swaps, Surround, hundreds.
Surrounds are kinda 101 for the DIY.

Unless you’ve listened to a surround swap, I just wouldn’t go there..

Get the surrounds from Wilson if you liked the performance you had.
Get the surrounds from someone ELSE if you want to change the sound..

BR will reduce the efficiency of the speaker.. Don’t believe, THEN READ..

A speaker manufacture will tell you just that.. Change the surround change the efficiency...
I do have some speakers with silicone surrounds.. Close in efficiency.

BR rubber is TOUGH, but not known for speed. Fabric on the other hand is probably the fastest and toughest.. Butyl Rubber works really well with high excursion drivers, Foams just won’t hold up.. Sense when did Wilson start using High Excursion drivers? Medium excursion and HIGH efficiency..

Happy Happy...

I like @artemus_5 analogy, and just to simplify it.

I called my local garage and asked if I could use Winter tires in the Summer, of course they said yes....

FYI - Wilson doesn't sell or do re-foaming, they use to suggest a third-party, but not sure if they do that now because that place has closed (orange county speaker repair). Lots of other places sell the re-foam kit though.

Keep in mind that just replacing the foam surround is only half the job. Best practice in most cases is to replace both the spider and surround. The spider is the more critical of the two suspension elements.

Keep in mind that many posting here...and even many repair shops don't really know what they're doing. The workmanship...or lack thereof..is evidence of that.

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.

I would agree with this.  The weight of the entire driver plus the weight and the "spring" strength of the spider will dictate the resonance frequency of the woofer.  This applies to port size tuning.  I don't think rubber/foam surround will affect the weight or spring/flex of the driver and have very little impact on resonance frequency.

Now the type of surround can definitely impact much higher frequencies (such as anything above 400-500 hz) because it affects the natural damping of the speaker vibration resonance.  This may have impact on frequency response or crossover design.  If it's a woofer on a 3-way speaker, then I wouldn't worry about replacing surround with rubber.

I was trying to find the crossover frequency. They are either a 3 or a 3.5 way. The mid-woof is quite large making me think the woofers are cutting over early. 

"You got some GREAT advise from a professional rebuilder, why are you asking."

I have known Bill LeGall for a long time.

Bill has re-foamed thousands of drivers.  Thousands, Thousands!

Have seen his work many many times.  I have re-foamed speakers myself.  Will it change the sound - sure it will - can you hear it - maybe - but the stiffness and the reaction time will change.  Some may hear that, other maybe not.  From seeing what Bill does, I can see the reaction time and how the driver reacts to music and how the driver moves in and out.  It is a science IMO.  So if I was you, just let Bill do them and be done with it once and for all.  You will not be disappointed with his work.

Happy Listening. 

I would stick to the original equipment as close as possible to make sure not to mess with or change the sound of the woofer the speaker refoam tech is right.