Foam vs Rubber surround

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W

walker

Member
2001-11-10 9:00 am
Perth West Australia
If it weren't for the dearly departed foam surrounds of my AR9's, (Acoustic Research), I would not have found this forum. So in a way I'm glad.
First question; where can I get replacements for the 12-11.5" woofers, (I have bought some 12"rubber surrounds but they do not fit).
Second question; I have already replaced the foam 8" surrounds with rubber surrounds, (on the lower mids). I have noticed a slight change, (Kings New Clothes?) but they still sound good. What are the pro's and con's of surround materials?
Thanks in advance for any enlightenment that you can offer.
Regards WALKER
PS Appologies if I have missed it thrashed out in the past, as I'm a newbie to this forum.
 
S

surfsun&sound

Member
2001-10-26 2:39 am
Sydney, Australia
Speaker Surrounds

Walker,

If you do not mind shipping your drivers I would highly recommend contacting Peter at Speakerworks in Concord, NSW. This gentleman has done nothing but speaker repairs for almost 30 years. I just spoke him to several days ago and we were discussing AR speakers and replacing the surrounds on them. He seems to have sources for surrounds that few people anywhere in the world have. He will sell you the surround for you to install. But for 10" rubber surround he will charge about $55 or he will fit the surrounds, shim and align the voice coils and supply a 2 years parts and labor warranty for $83. You take your pick, I am sure that you can guess what I choose.

Peter - Speakerworks

02 9746 5754
0407 932 294

http://www.speakerworks.com.au

By the way if you have an ideal where I can find a pair of AR-94's, I would be a friend forever. I have scrounged the US and since I moved to Sydney I have been looking everywhere and have come with zip. I want a pair of AR-94's any almost any condition very desperately.

Cheers,

Surf, Sun & Sound
 
S

surfsun&sound

Member
2001-10-26 2:39 am
Sydney, Australia
AR - 94 Brochure

Walker,

Is there anyway that you could copy that brochure and send me a copy or scan it and post to the net? I have very limited information on the speakers except what I can get off the web which is not much. The only really good source on the net is an article on

http://www.tnt-audio.com/clinica/ar94rebuild_e.html

I have been searching E-bay and the net for almost 2 years and information about AR speakers is scare in general.

What do you think,

Surf, Sun & Sound
 
B

bawang

Member
2001-10-31 2:52 am
Malaysia
About foam vs rubber surrounds for speakers..... Well, I would ALWAYS recommend rubber. I own an excellent pair of Paradigm 3se mini and they sound excellent, until the foam surrounds die (ie rot) after 2 years in this tropical weather. Contacted Paradigm and bought a replacement set for the woofer/midrange units, but these too rotted after less than a year. Paradigm replied that this is impossible, but I have 2 sets of woofers/midranges to prove it.

Changed the surrounds for one set on my own, but the sound character changed for the worst. I still have the other set with rotted surrounds........

I am now using a pair of Monitor Audio 7 (for my bedroom) and a pair of Robertson Audio Silver 30 for my lounge. An you guess right, both have rubber surrounds. Have used them for 3 years without any problems......
 
T

tomcat

Member
2001-09-30 10:36 pm
Sth. Oz
Beware changing foam surrounds to rubber! The advantage of foam is better cone edge termination, hence smoother response. Changing to rubber may sound attractive from longevity point, but will result in a driver with a totally different response (characteristics) to what it was before, in effect it becomes a different driver which will affect all facets of performance especially through the x/over! There is nothing wrong with foam, sure it breaks down after 14 years, but it is relatively cheap and easy to fit a new one, and you are set again for another 14. Keep it original and enjoy the sound...
tomcat
 
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surfsun&sound

Member
2001-10-26 2:39 am
Sydney, Australia
Tomcat;

I agree that you have to careful about changing surround materials on drivers, I also know that heat and humidity of the tropics will end the life of foams surrounds very prematurely. So in those climates I give a definite edge to rubber surrounds.

Bawang;

There are different qulities of foam surrounds, so be sure that you get the best that you can find if you are going to use foam in the tropics. I would recommend having a professional replace the surround with rubber and they will be able to provide you with the new parameters to determine if the changes are enough to warrant changes to your boxes.

In my experience, rubber can be used to replace foam if it is done by profeesional(meaning someone who done at least 100 pairs of drivers and aligns and tests the driver after the swap).

Peter of Speakerworks comes highly recommended and his information is in a previous post to this thread.

Surf, Sun & Sound
 
W

walker

Member
2001-11-10 9:00 am
Perth West Australia
I have had it suggested to me that rubber surrounds age as badly as foam. I guess it depends on the type of rubber used.
I have stocks of speakers over 10yrs old and a quick check found SOME of those with rubber surrounds in poor condition (even though they have never been installed). In fact the foam surround drivers on stock, (also years old) seem to be in better condition generally, at a loss to explain why.
So there you go, the cat is amongst the pidgeons!
I have noted that the better brands seem to have aged less, no suprise.
I now suspect that many speakers with rubber surrounds have aged, (gone soft or hard) but because owners don't see them disintergrate they believe that they are still in good condition.
Your thoughts gentlepersons?
Regards WALKER
 
P

pkgum

Member
2001-10-27 4:56 pm
sydney
treated foam surrounds

rubber does NOT age as badly as foam. rubber is nearly always more durable than untreated foam. The rubber surrounds in the speakers u stock are probably really poorly made if they age faster than foam.
can rubber go soft or hard when it ages?? I didn't know that.... I have a pair of speakers that are 25+ years old and their rubber surrounds on their 10" drivers are as flexible and durable as it was new. BTW i don't believe properly made rubber can disintegrate in only around 10 years. Very very rarely can untreated foam be more durable than rubber.
.........................................................
read the desription of these series of drivers
http://www.blueprintdrivers.com/03.html

It has treated foam surrounds. Whats the difference between treated foam surrounds and normal foam surrounds?lasts longer? Will the treated foam surrounds last well in the tropics?

[Edited by pkgum on 11-13-2001 at 01:37 AM]
 
W

walker

Member
2001-11-10 9:00 am
Perth West Australia
The aged rubber surrounds that I have are on SOME CHEAP drivers that I use went customers want a cheap repairs on no-name noisemakers, (read speakers). A couple of rubber surrounds have gone soft and tacky and one is noticeably stiffer than it was when new.
All the foam surround drivers were packaged in a plastic bag with a small satchet of silica gel the rubber driver are not. Mabe the comparison was unfair.

I have replaced the foam surrounds on some of MY own drivers with rubber ones and hope that they will outlast the original surrounds, only time will tell.
At the moment I believe that most quality brand rubber surrounds will outlast foam surrounds. I do know that the type of rubber used varies between manufactures and on cheap drivers it can age.
I have also heard of foam surrounds treated to resist rotting/aging.
Hoping this sets the record straight, the previous posting may have been missleading.
Regards WALKER
 
S

surfsun&sound

Member
2001-10-26 2:39 am
Sydney, Australia
For Whatever it is worth!

walker and pkgum,

I believe that we all are on the same wavelength here about the different surround materials used. I am a industrial and furniture designer by trade, so I can tell you from experience(not necessarily on speakers though) that there are many factors that can shorten the life span of a product.

Yes, I have a pair of drivers with rubber surrounds that have gone brittle and are starting to crack, although they are probably 20 years old. My experience with rubber versus foam is that rubber will deteoriate gradually where as foam will have a sudden death. Similar to the steel versus aluminum argument, steel is will flex more under load, is heavier, and as it fatigues will sag or relax over time and the point of failure will be detected by these traits, where as aluminum is more rigid and will flex much less under load over time, but will fail suddenly with very little warning but with catastrophic consequences depending on the application. I know this from designing mountain bike frames and there was much argument about which material was the best for many years in this application.

OK, now that I have bored you to death with some totally unrelated information, here is my conclusion based on my own experiences, rubber will outlast foam of equal quality(high quality foam will outlast cheap rubber and vice versa) under the same enviromental influences, but throw in extremes of humidity, heat, cold, overexposure to sunlight even through a window and you will dramatically shorten the life of either product. I believe that the worst enemy to any material, even we humans, is UV radiation which can reflect off of most any surface and penetrate a large majority of fabrics and materials.

You may be committed to replacing your surrounds with original material to maintain the correct parameters. That is why I recommend have a professional replace the surround since they will the experience to predict the end result and advise you the correct replacement.

Cheers,

Surf, Sun & Sound
 
T

tomcat

Member
2001-09-30 10:36 pm
Sth. Oz
I don't want to buy into any argument vis-a-vis which material used for surrounds is the most durable...
All I am saying is that it is a given that changing the surround from foam to rubber will alter the drivers characteristics. Full stop!
On the subject of rubber surrounds, about 7 years ago I had to have a pair of Kef B110's reconed as the rubber surrounds began to crack along the top of the roll. This was very subtle and was only visible on close inspection manually moving the cone backwards and forwards, yet in every other respect it was almost undectable.
tomcat
 
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surfsun&sound

Member
2001-10-26 2:39 am
Sydney, Australia
Mother Nature Never Gives Anyone a Free Lunch

Tomcat,

You are exactly correct, changing surround materials will change driver parameters. Full Stop!! Agreed!!!

The subject of durability arose since there are a few of us who live in climates that are not very friendly toward speaker surrounds of any type.

You can never cheat Mother Nature, foam does make a better surround material, but is more sensitive to enviromental conditions and not as durable as rubber. But eventually both will wear out. Even changing or replacing the surround with the same material in my experience will change driver parameters to some extent. That is why there is a break in period for new drivers. There are very few of us that go to the extra effort of breaking a set of drivers and then taking the parameters needed to design a pair of speakers. Definitely no commercial production concern has the time or the economics to do that.

So unless you break in all your drivers before designing, even the most meticulously designed and built speaker will changeover time, some more and some less depending driver quality.

Mother Nature never gives us anything for free, so we end up choosing the best compromises.

So Tomcat is exactly correct about driver parameters changing, and the best way have least amount of change is to have a skilled and trusted professional do the job.

Surf, Sun & Sound

Regardless, music is the most important thing.
 
G

GRollins

Member
2001-02-23 3:46 am
Columbia, SC
Although I've seen it claimed many times, not once have I ever seen any bona fide evidence that foam surrounds are, in fact, superior in any way (other than being cheaper) to rubber surrounds. Every time I've heard it said, it was always by someone who had a financial stake in the claim that foam was 'just as good' or 'better.' Either they were trying to sell you their product, or they were trying to rationalize having bought such a product in order to save a buck.
It reminds me of the way that people who sell or purchase mobile homes (nowadays we're suppoed to call it manufatured housing) always want to insist that they're 'just as good' as homes built on site. Right. Sure thing. If, for financial reasons, you're forced into buying a mobile home in order to have a roof over your head, at least be honest about it.
There certainly isn't any audible justification for the claimed superiority of foam surrounds. There's no trend towards their use in high-end speakers--can't think of a single one offhand--only cheap to mid-fi speakers. No one I know has ever said that they really like the sound of foam surrounds. I tolerate replacing tubes because they do some things audibly better. I do not tolerate foam surround failures because there's no audible benefit to balance the scales; there's no earthly reason to saddle yourself with a reliability problem that you can easily avoid for a few extra dollars.
The only failures I've seen in good quality neoprene surrounds are when they've been continuously exposed to sunshine or fluorescent lighting (UV is hard on any synthetic), but even then foam surrounds deteriorate far more quickly.
I have quite a few drivers that date from as far back as the '70s. Every one of the rubber surrounds are intact. Not one of the foam surrounds survived. Promises that 'we've got a new formulation that's good forever' have always proved to be lies in the past. I no longer listen to such noise, although I'm sure at some point they will finally get it right. One of the things that I find rather bothersome about manufacturers who build drivers with foam surrounds is that they have this rather predictable habit of being out of business when it's time for the inevitable reconing. Then you're left with the option of putting in a generic surround with different characteristics (thus changing the driver unpredictably) or throwing the remains of the driver into the junk box. That never seemed like a good option to me. I try to build stuff to last--not as an exercise in planned obsolescence.
In short, it ain't worth it. You may save a dollar or two now, but it comes back to haunt you later. Buy quality. It pays.

Grey
 
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