Jump to content

Compliance of replacement foam surrounds


Rich W

Recommended Posts

Thanks RichW

Boy PE is proud of their kits

I've got a line on some others-foams only that measure Outside Edge-7,75" and inside 5,5"

Do you have any of those PE ones to see how that compares?

I have some on hand that measure-7 7/16 x 5 1/4

Looks like the originals were 7 3/8" x 5 9/16

I may sound like a broken record here (remember those?), but I highly recommend MSound. No--I'm not affiliated with them in any way.

Here is what I recently wrote in the Advent area:

I highly recommend MSound:

http://www.citlink.net/~msound/

I have found John to be extremely helpful, his kits are VERY complete, and he is responsive to your needs (want a different dust cap? He has it). His incomplete website does give very good step-by-step instructions. I have used his kits for Allisons, ARs, even 4" AR Partners. His order form asks a lot of questions and asks for a lot of measurements so you get the right thing. He will answer any questions by email promptly.

All surround kit sellers get their foam surrounds from the same source. It's the care, completeness of the kit, and quality of the support that makes a difference. I got screwed once by a well-known seller who did not include dust caps or shims. Their attitude: If we don't have it, you don't need it." Caveat emptor :)

Kent

Link to comment
Share on other sites

I just completed restoring my AR-6's. I emailed M-sound twice without ever receiving a response. At that time they had a generic 8 inch surround kit and didn't specify the AR models as they do for the AR-3 surround. As far as I concerned, they don't offer customer service.

I settled for Vintage-AR. I wasn't particularly happy with this kit as the glue dries so quickly, you can't afford a mistake when dropping the surround onto the frame. I was just a little off, and it wouldn't budge. The installation instructions were barely adequate I must admit M-sound's web site did help me gain an understanding for the surround replacement.

Link to comment
Share on other sites

I just completed restoring my AR-6's. I emailed M-sound twice without ever receiving a response. At that time they had a generic 8 inch surround kit and didn't specify the AR models as they do for the AR-3 surround. As far as I concerned, they don't offer customer service.

I settled for Vintage-AR. I wasn't particularly happy with this kit as the glue dries so quickly, you can't afford a mistake when dropping the surround onto the frame. I was just a little off, and it wouldn't budge. The installation instructions were barely adequate I must admit M-sound's web site did help me gain an understanding for the surround replacement.

Hi there;

I've read about every writeup about surround replacement done here by members.

Very few ever wrote a negative comment about the results.

The actual surround material has varied in quality, density and profile though.

I even wrote here once commenting, complaining to be more precise, about the lack of identification on any foam surrounds.

We, as consumers, cannot just order, model such and such, made by ABC Manufacturing and be certain of receiving the same product as our last purchase.

There is more than one manufacturer of surrounds.

You can look back in the write-ups, probably the AR, preferred, and see that an order from one source is different in profile from another.

Until foam manufacturers start labeling the surrounds, we will be hearing more about this issue.

We are at the mercy of where we buy from and they in turn are at the mercy of whom they buy from, which can change due to no stock, cheaper price, or manufacturer is out of business.

The adhesive available to us, locally at retail, is, Permatex No. 98H UPC 80543 in 118 ML tin High Tack Gasket Sealant.

Another adhesive commonly used here in Vancouver, by myself as well, is, 3M #847 Rubber and Gasket Adhesive.

These are both a dark coloured adhesives and one should read their MSDS sheet prior to using.

Both can be obtained from almost any autobody material supplier in small quantities.

The white adhesive shipped with some surround kits is mailable, these two are not.

There is not even an agreement here, as to whether the shims should be used, when included in the kits.

Of course at the factory, they used shims when the dust cap was not attached yet.

I've re-foamed with and without the shims.

My first one was, an AR-3A 12" woofer, it took me 1 1/2 hours roughly for the job.

The second one about 10 minutes.

With the large voice coil gap in most classic woofers, we can usually just gently rock the cone back and forth to center them, rather than shim, which would requre removing the dust cap, of course.

With JBL, EV and Altec, for just three examples, shim's are required, as the gap is very fine.

For the most perfect of voice coil alignment, shim's should be used.

Business card stock work's well for shim stock for AR etc.

Link to comment
Share on other sites

I've got a line on some others-foams only that measure Outside Edge-7,75" and inside 5,5"

Do you have any of those PE ones to see how that compares?

I have some on hand that measure-7 7/16 x 5 1/4

Looks like the originals were 7 3/8" x 5 9/16

Hi Windwalker,

Here's the specs on a spare PE 8" surround I have.

Outer diameter: 7 3/4"

Outer edge of roll diameter: 7 1/8"

Inner edge of roll diameter: 5 7/8"

Inner diameter: 5 3/8"

Hope this helps.

Best Regards,

Rich W

Link to comment
Share on other sites

I just completed restoring my AR-6's. I emailed M-sound twice without ever receiving a response. At that time they had a generic 8 inch surround kit and didn't specify the AR models as they do for the AR-3 surround. As far as I concerned, they don't offer customer service.

I settled for Vintage-AR. I wasn't particularly happy with this kit as the glue dries so quickly, you can't afford a mistake when dropping the surround onto the frame. I was just a little off, and it wouldn't budge. The installation instructions were barely adequate I must admit M-sound's web site did help me gain an understanding for the surround replacement.

I'm very sorry to hear about your experience with MSound :( John, the owner, is usually very responsive and he does have a variety of sizes and styles. I know he is not in good health, so he may have been ill when you emailed.

I know what you mean about the glue! MSound and others use a white glue similar to Alene's Tacky Glue and it works well. The company I had a bad experience with (S***** S*******) used something more like contact cement and as you noticed it does not allow for alignment corrections.

Sorry to disagree with Vern, but I would not use gasket cement. There was a recent thread:

http://www.classicspeakerpages.net/IP.Boar...amp;hl=permatex

in which RoyC recommended a Permatex product for sealing CLOTH surrounds, and warned that the solvent could attack the foam in a foam surround, so my advice would be to stick :) with the white glue from MSound, Parts Express and others.

Kent

Link to comment
Share on other sites

Kent.

Thank you for your response. I wish I had known before using the surround cement. I can't explain it, but my speakers meant a lot to me. I would like to do them over, but not sure I can remove the cement from both the surround and dust cap. Anyway, like I said, I can't explain it, but when I connected my AR-6's for the first time in nearly 30 years, they brought tears to my eyes. The sound certainly isn't as accurate as my main system, but I became more connected to the music. It's a sound that, as I was developing as a teen, became part of me. When I heard some those hits from Motown, its as if I was taken back to those years. I want to do everything I can to ensure these new surrounds will last for a long time. I painstakingly spent probably more than 100 hours bringing these speakers back to life. I am now in the process of trying to add a Dynaco Stereo 70, PAS-3x, FM-3, AR turntable and maybe even a tape player like my Ampex.

As for M-Sound, because my first email was send within eBay, and the second to their own email address without any reply, I simply thought they lacked customer support because within those weeks of waiting for a response, they were adding new items to eBay.. Darn, I wish I installed their surround instead!

If you have any advice regarding the removal of these surrounds, or any other advice/comments, please let me know.

Thanks,

Larry

Link to comment
Share on other sites

Kent.

Thank you for your response. I wish I had known before using the surround cement. I can't explain it, but my speakers meant a lot to me. I would like to do them over, but not sure I can remove the cement from both the surround and dust cap. Anyway, like I said, I can't explain it, but when I connected my AR-6's for the first time in nearly 30 years, they brought tears to my eyes. The sound certainly isn't as accurate as my main system, but I became more connected to the music. It's a sound that, as I was developing as a teen, became part of me. When I heard some those hits from Motown, its as if I was taken back to those years. I want to do everything I can to ensure these new surrounds will last for a long time. I painstakingly spent probably more than 100 hours bringing these speakers back to life. I am now in the process of trying to add a Dynaco Stereo 70, PAS-3x, FM-3, AR turntable and maybe even a tape player like my Ampex.

As for M-Sound, because my first email was send within eBay, and the second to their own email address without any reply, I simply thought they lacked customer support because within those weeks of waiting for a response, they were adding new items to eBay.. Darn, I wish I installed their surround instead!

If you have any advice regarding the removal of these surrounds, or any other advice/comments, please let me know.

Thanks,

Larry

Hi Larry

Yes--I think the problem you had with MSound was due to using an email program that filtered out spam and it saw the reply as spam. I just emailed John (on a Sunday) and he got right back to me. He thinks the problem was your spam filter because he is scrupulous about answering emails.

I would suggest you contact him again and ask his advice about removing the cement if you are dissatisfied. If you end up buying a new kit from him, another $20 or so is a small price compared to what you have invested in blood sweat & tears already.

btw--here is some additional info from MSound:

BTW... I did read the thread... & noticed that someone mentioned I only offered a Generic 8 kit and not what models it fit. The reason is it fits virtually ANY AR 8" as AR tended to use very similar foams in everything AND primarily there are not that many different 8" foams available now. and ARs 8s don't require a special kit like the AR-3's; an 11". You might mention to the folks on the group that they CAN do something that would help US when they order a kit. THEY could take a pro-active position in ordering a kit and tell US what they want out of a kit... specifically whether they are looking for a heavy duty foam (IE: a few more years of use) or a more compliant Foam-Hi Performance Surround... IE: such as a JBL Foam. In the case of any AR 8" foam I can & DO offer TWO surrounds for these applications IF customers would state which they would prefer.

Good luck

Kent

PS Your dream system sounds a little like my first system in the late '60s: I used a Dynakit ST-35 tube amp, dynakit PAT-4 transistor preamp, KLH Eighteen tuner, AR turntable & AR 4x speakers. Still have the tuner and listen to the speakers daily. The rest went on ebay (that ST-35 appreciated in value tenfold!!)

Link to comment
Share on other sites

Kent,

Yes, your system was similar to mine. I had an ST-35 and AR-4x's too, but when I got the AR-3's, I needed more power, so I moved up to the Stereo 70. Later I got a Stereo 120 and PAT-4. Big mistake! The Stereo 120 caught on fire and burnt out the mid's and tweeters in the 3's. I was so bothered by this, I threw out everything (no eBay in those days), and bought McIntosh/JBL/Thorens/Revox (big in the early 70's). I later wanted quadraphonic, so I added another McIntosh power amp, and bought a pair of AR-6's for the rear speakers. That's where the AR'6's came in.

As for my email program, I'm running Linux/Ubuntu. I don't have a spam filter, and have NEVER received spam. My email address is pretty complicated (I use a combination of letters, numbers and symbols).

I will send John an email, and ask for his opinion. I would like to redo my surrounds if possible.

Thanks again,

Larry

Link to comment
Share on other sites

As for my email program, I'm running Linux/Ubuntu. I don't have a spam filter, and have NEVER received spam. My email address is pretty complicated (I use a combination of letters, numbers and symbols).

I will send John an email, and ask for his opinion. I would like to redo my surrounds if possible.

Thanks again,

Larry

Hi Larry

John seemed quite concerned that a customer would think he had ignored him. He went back to his emails and found that he had replied to you, but the message went thru ebay and their system seems to filter out HTML messages. May not be a bad idea, to prevent scams, but it hurts legitimate correspondence.

Here is John's advice to us all:

This is something I clearly ask folks NOT to do. IE: mail me thru ebay! Their system is NOT reliable and it OFTEN filters HTML mail! especially IF I send folks a link back for an offer, such as with a PayPal payment icon (Like we've often used). THIS is something folks on your groups need to be told. DO NOT REQUEST ANYTHING THRU EBAY FROM A VENDOR! EBAY MAY FILTER IT. Especially IF it contains a HTML & or Links which their email can't handle!

FWIW

Kent

Link to comment
Share on other sites

Kent,

I emailed Msound through eBay yesterday. I received a response today. Whomever it was, didn't acknowledged their name; nevertheless, I did receive a response. No software changes here.

Thanks for your help. I didn't mean for you to be the middleman.

Sincerely,

Larry

Link to comment
Share on other sites

Guest Audiomark

Speakerbits (Melbourne, AUS) have a part no. "082" which is a thin, light-grey coloured surround for the AR18, etc.

Comparing a driver that I refoamed with this surround, to one that had been refoamed with a "universal" dark grey surround, there was a 5 Hz difference in driver Fs, which is significant.

Link to comment
Share on other sites

Darn! Darn! Darn! Wish I had known about Speakerbits 2 months ago. I only assumed because the seller where I purchased my surrounds once worked at AR, this would be the best choice. Hopefully others will read your reply too. Anyway, thank you for the information!

Link to comment
Share on other sites

Guest windwalker

Wow, Take a couple days away and look at all the good information

I like knowledge

RichW, thanks for the measurements

Audiomark, speakerbits-NICE site, a bookmark for sure. 5Hz pretty significant

I have a couple 8" foams here from various vendors. let's see how they compare.

But like someone mentioned-we're rather at the mercy that vendors we buy from get the same stock every time(doubtful)

I still have an original to measure from, they are

O- 7 3/8"

OR- 7"

IR- 6"

I- 5 5/8"

Foam 1-from a member on audiokarma

O- 7 1/2"

OR- 7"

IR- 5 13/16"

I- 5 1/4"

Foam 2-From matelectronics

O- 7 3/4"

OR- 7 1/16"

IR- 5 15/16"

I- 5 3/8"

and from speakerbits, their 082K(hope my math is right and i used some rounding as most of us don't measure in 25ths and such)

O- 7 2/3"

OR- 7 1/8"

IR- 5 15/16"

O- 5 11/32"

Please add yours, if you have em. And where from

Thanks

/small rant

I'm sure everyones' kits are great but I normally don't buy kits. Why?

I don't need more glue-use Aleenes's, works fine

I don't need Shims, use a 1.5 volt battery and touch\feel

Don't need dust caps because I don't shim

The kit part is where they make their money-fine but I just need FOAM

/rant off

Link to comment
Share on other sites

I like your approach. Can you please elaborate regarding "I don't need Shims, use a 1.5 volt battery and touch\feel"? I may redo my surrounds, and would rather leave the dust cap there. I already replaced it once, and feel if I had to remove it again, it will probably do some damage to the cone (due to the fact the replacement dust cap is at least twice the size as the original).

Link to comment
Share on other sites

Much frustration has been expressed in the threads here regarding foam surrounds. Acquisition problems by DIY'rs include both size and compliance properties. Size obviously affects fit into the driver, but also can affect the compliance (e.g. the roll geometry).

If I can assume for purposes of this discussion the size-to-fit problem can be overcome, what remains regarding the critical function of the surround is its compliance properties which are affected mostly by materials of construction, thickness and geometry.

Granted, the spider is known to have a significantly greater effect on a driver's total compliance than the surround. However, spiders don't rot and generally last much, much longer than foam surrounds. Albeit, I have seen accasional evidence of collapsed spiders which, I theorize, occured due to storage of the driver over a long period of time with its axis pointing up and down rather than the normal side-to-side orientation.

I briefly did some thinking about developing a test method for compliance, but wisely decided to conduct some research to see if this 'wheel' had already been invented. Sure enough, ALMA (American Loudspeaker Manufacturer's Associstion) has a standard test method (TM-438) to measure that very property. There are 2 methods within the method. The first involves a rather tedious and perhaps outdated, manual method using weights. The second method uses modern force/distance electronically controlld (computer interfaced) techniques involving an instrument developed by an Asian company called Tonwel Co., LTD. So, now we know there is a method and it follows then, there MUST be specifications out there for surrounds being produced today. However, I am not aware of any of this information being shared with bloaks like us who buy and used them.

Theil and Small created a set of standards for driver performance - all of which can be measured and/or calculated from limited test data. These standards are in use today and many of you may have referred to them when making a driver purchase.

Why then, can't the same thing be done for surrounds - both foam and rubber? I can only speculate that our market is too small to encourage adoption of quotation of surround compliance characteristics. It's kind of like the AR 3/4 inch dome tweeter reproduction problem - not enough justification to make a special run to closely duplicate the original design.

OEM suppliers of surrounds most likely share surround specs with driver manufacturers. These days, I suspect, driver design engineers can basically construct a functioning woofer on their computers by inputting a myriad of component properties - including compliance properties of spiders and surrounds.

Perhaps an industry guru or two can offer some advice here on how we, the DIY'rs, can have a voice in encouraging the surround manufacturers to provide compliance characteristics for general use. After all, it's already been done for T/S parameters. Thousands of vintage speaker owners are discovering each day their beloved speakers don't woof any more. I believe the problem here is much bigger than the AR 3/4 inch dome tweeter problem. Just look at all the sellers out there of foam surrounds and kits!

Link to comment
Share on other sites

Why then, can't the same thing be done for surrounds - both foam and rubber? I can only speculate that our market is too small to encourage adoption of quotation of surround compliance characteristics. It's kind of like the AR 3/4 inch dome tweeter reproduction problem - not enough justification to make a special run to closely duplicate the original design.

I suspect it's worse worse than "not enough demand." If the foam parts in the refoam kits are manufactured by the same OEMs who supply foam to driver manufacturers, the specs on the foam parts in the JBL xxxx woofer would most likely be a big no-no in their OEM contract with JBL.

Releasing specs on generic foam parts might be doable, but then how are you going to find out which generic part is in JBL xxxx unless JBL is willing to share (and the chances they will are nil)?

Then, of course, there's the fact that many classic speaker manufacturers and the companies that supplied drivers to them are now defunct and their engineering records lost to the ages.

The only way you're likely to get this kind of info on surrounds is if someone who doesn't supply parts to driver manufacturers makes surrounds and sees a return in analyzing other companies' speaker drivers to try to match their specs, which is going to be great fun if the only original drivers available to analyze are all 30+ years old.

Link to comment
Share on other sites

, which is going to be great fun if the only original drivers available to analyze are all 30+ years old.

There may be some information to be gleaned from the nearly 500 drawings in the Ken Kantor batch Mark is trying to put in the archives. He was having some difficulty in creating a user interface linking a drawing description to its image file. I think I recall a couple of comments about foam brand/part number/density and other parts specs when doing part of the indexing. I'm not sure if Bret remembers any details after scanning them either; it has been some time. Hopefully Mark will have that problem solved soon! Even so, its not a given that a current resin maker would know the composition of that resin- depends on what records are available.

Cheers,

Link to comment
Share on other sites

I suspect it's worse worse than "not enough demand." If the foam parts in the refoam kits are manufactured by the same OEMs who supply foam to driver manufacturers, the specs on the foam parts in the JBL xxxx woofer would most likely be a big no-no in their OEM contract with JBL.

Releasing specs on generic foam parts might be doable, but then how are you going to find out which generic part is in JBL xxxx unless JBL is willing to share (and the chances they will are nil)?

Then, of course, there's the fact that many classic speaker manufacturers and the companies that supplied drivers to them are now defunct and their engineering records lost to the ages.

The only way you're likely to get this kind of info on surrounds is if someone who doesn't supply parts to driver manufacturers makes surrounds and sees a return in analyzing other companies' speaker drivers to try to match their specs, which is going to be great fun if the only original drivers available to analyze are all 30+ years old.

I disagree Genek. The speaker driver scenario is a glaring example of a market demand being filled by what I am sure are OEM suppliers (among them). Parts Express, Madisound and others have many examples. Each driver comes with some specs the buyer can use to decide which is best for him or her. These same suppliers are making drivers for many speaker manufacturers. Vifa and Seas did this for many years. The part numbers were a bit different, but exactly how different were they? Only they know. JBL may not be worth discussing within this topic because they tend to produce most of their stuff in house.

Even if an OEM surround supplier was making stuff for JBL, they could still sell a NOS copy to the rest of us and not tell how close it is to a JBL original. Who do you think is making that store brand of Wheaties sold at a lower price? More than likely it's General Mills; although they don't make light of it. I worked in an industry that serviced the food industry and saw numerous examples of off-brand products being made by brand name food Corps. that are very similar to their original brand names.

The point here is if a DIY'r is looking for some surrounds, he/she now has to rely ONLY on assurances from people he most likely doesn't know. They could be the kit suppliers or posters on the myriad of speaker discussion forums on the net. OTOH, having a compliance measurement standard in place provides the means for a basis for comparison for the window (internet) shopper. If you were shopping for a woofer for your home built AS speaker project and had to choose between two 10 inch drivers of similar size and not knowing much more, wouldn't you rather know one had an Fs of 20 hz vs the other with an Fs of 45 hz and the 20 hz model was best suited for an AS design, whereas the 45 hz model was best suited for a ported design? The same applies to basic information on foam surrounds that could and should be available for ther rest of us - not just the driver manufacturers.

With regard to vintage surrounds, yes it's obvious there probably isn't much info. available. However, some test data or specification is still better than none. One could find a surround most suitable for let's say an AR3a or Advent driver to yield driver test data close to original. A group of surrounds from the same production batch could then be measured using the ALMA test method and a compliance spec established to accomplany size information. Similarly, the same process could be done for numerous other classic drivers. If the original production specs for classic woofer surrounds can be found, all the better. But I wouldn't hold my breath.

Let's start now to compaign to find a way to convince surround manufacturers to come forward and realize there is a significant DIY"r consumer market that now shops 'in the dark' so they can begin to cooperate and share information.

Link to comment
Share on other sites

The speaker driver scenario is a glaring example of a market demand being filled by what I am sure are OEM suppliers (among them). Parts Express, Madisound and others have many examples. Each driver comes with some specs the buyer can use to decide which is best for him or her. These same suppliers are making drivers for many speaker manufacturers. Vifa and Seas did this for many years. The part numbers were a bit different, but exactly how different were they? Only they know.

Yes, and they're not telling. Even driver manufacturers that supply drivers to DIY'ers don't provide specs on foam compiance, voice coil desgn, etc., just the specs of the finished drivers. They want you to buy their drivers to build your speakers, and to buy their drivers again when the original drivers wear out.

Yes, it's possible for OEM manufacturers to sell DIY parts that are similar or even identical to what they're providing to their wholesale customers. In fact, my guess is that most of these DIY refoam kit surrounds are exactly that. What you are NOT going to see, at least not as long as the OEM's customer is still in business and capable of being a viable customer or suing the pants off them, is them selling you a part and saying "equivalent to <insert driver mfr P/N here>." Yes, they could tell us what the compliance of the generic foam is, but again, if the company whose driver you're trying to refoam isn't telling what compliance foam is in their woofer, their OEM part supplier isn't going to cheese off a good customer by telling you either. That off-brand Wheaties substitute may well be Wheaties in a house brand box, but you are not ever going to see "Wheaties" on that house brand box.

Of course, in cases like AR, where the company itself has decided to turn their engineering drawings and specs over to the public domain, there are no trade secret or other IP issues, and it really is a matter of whether or not there's a demand. Otherwise, it's not the surround manufacturers you have to convince, it's the speaker manufacturers.

Link to comment
Share on other sites

Guest windwalker

Golly and all I was looking for was the closest to the correct size

I believe I'm going to give the ones I got from Mat a go. They're not that far off.

Be nice if I could combine the best dimensions of the group and make my own

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...