Does Replacing Surrounds Degrade Performance?

[titanstats]

Speaker repair guys are in the business of repairing speakers, NOT selling inexpensive surrounds, and they understandably do their best to discourage those who would DIY.

That there is the truth. That being said, a good refoam job should return a driver to its original condition. If the correct foam is used (and the rest of the driver is still in good condition), I can't imagine that it'll measure any differently when restored.

Keep raccooning those woogers, boys.

 

[sealy]

Pure codswallop!

 

[Title17]

personally speaking, I would rather have a well refoamed set of speakers then unoriginal replacement drivers. however quality work is a must.

 

[marantzfan]

Several people here with adequate measuring equipment. tallent and time CAN verify that refoaming is typically a reliable way to reuse the same drivers AND get as good, if not better, specs than what the speaker came with. It is simply not a black art to stay away from but a great, inexpesive, relible way to revive a good speaker.
DC

Quoted for truth. I just did my first refoam job on a pair of Infinity RSIIIB's....Four watkins woofers in all..

They sound outstanding and I am convinced that if I can do it, anyone can. Just take it slow and be careful...

 

[gkimeng]

That there is the truth. That being said, a good refoam job should return a driver to its original condition. If the correct foam is used (and the rest of the driver is still in good condition), I can't imagine that it'll measure any differently when restored.

"Correct foam" is the key. With the exception of those rare driver manufacturers who actually make factory rebuild kits available, there is no certain way to know what "correct foam" is for any particular driver. The speaker manufacturers don't publish component specs down to the level of surrounds, and if they oem source their drivers, they may not even know what the specs are for parts of drivers they buy from vendors by the specs of the assembled driver. Add to that the fact that you may be trying to repair items that haven't been made in decades by companies that haven't existed for decades and have no examples of new items to measure them against, and in many cases you are essentially right back where people like Villchur, Kloss and Burhoe were in the last century: trying what's available and seeing what combinations actually produce the sound you think you're looking for. What better definition of "black art" do we need?

Today I can tell you that my newly refoamed AR-3a woofers sound just fine to me. Can I tell you that they sound exactly the same as a brand new one did in 1975? No. But the guys who sell the brand new service replacements for $160 each can't tell you theirs does, either.

 

[Zilch]

So, tell us, who is the leading manufacturer of quality replacement surrounds, and where may we review their factory specifications?

Now, y'all are slipping into Zilchification territory:

"I don't know if it sounds like the original or not, but it sounds good to me."

So, in detail, we don't care if it's actually performing as original or not, rather, merely that it has some semblance of original and is cheap?

[Sounds like Classic Speaker Pages.... ]

 

[kcollins4]

So, tell us, who is the leading manufacturer of replacement surrounds, and where may we review their factory specifications?

Now, y'all are slipping into Zilchification territory:

"I don't know if it sounds like the original or not, but it sounds good to me."

So, in detail, we don't care if it's actually performing as original or not, rather, merely that it has some semblance of original and is cheap?

[Sounds like Classic Speaker Pages.... ]

A slippery slope indeed.

 

[gkimeng]

So, tell us, who is the leading manufacturer of quality replacement surrounds, and where may we review their factory specifications?

Now, y'all are slipping into Zilchification territory:

"I don't know if it sounds like the original or not, but it sounds good to me."

So, in detail, we don't care if it's actually performing as original or not, rather, merely that it has some semblance of original and is cheap?

[Sounds like Classic Speaker Pages.... ]

Well, I'm able to do a little better than that. At least I actually have heard brand new AR-3a's, as well as 5's, 2ax's and 6's in the same state. I own 2ax's and 6's that I have anal-retentively maintained through the years, and can tell you that the newly refoamed 3a's have a sound that fits what I remember between the models when they were new. But filtered through 30 year old memories and whatever hearing changes I've experienced through the years, no, it is not possible for me to state they sound exactly the same as new.

Cheap is not that important. If the folks at ABTechservices could guarantee their replacements were exact duplicates of the originals, I'd have dropped the cash for new in a heartbeat.

The most recommended (not "leading") replacement surrounds for AR woofers come from Vintage_AR. Factory specs? Not a one, performance totally anecdotal. And yep, most of the anecdotes do come from the rest of the folks on CSP. The point was, most times "sounds good," or "like I remember it" is the best that can be achieved because there is no alternative that assures a more authentic result, not "I don't care if it sounds original." I sure as hell do care. It's just that this is the best that can be done and I'm not going to delude myself that I've done better.

 

[whoaru99]

Let's see...

I have a speaker with bad surround that I can't use, OEM replacements aren't available, but I can have new surrounds (or recone) put on to make the speakers work again.

Does it change the sound? Maybe yes, maybe no, probably hard to say...

But, what other choice is there except to refoam/recone (assuming scrap pile is out)?

 

[dc270]

Has no one here actually measured a refoam product and then compared it back to a published spec?
DC

 

[Dan ʕ•ᴥ•ʔ]

Has no one here actually measured a refoam product and then compared it back to a published spec?
DC

Which should be the final step. If the repair has measurably altered the driver's response, then it hasn't been a successful repair IMO.

 

[similost]

Some of us prefer drivers with paper or cloth surrounds, so we just don't worry about this.. I've passed by many speakers because I just didn't find them worth the effort to refoam, or the fact they did have old foam that didn't look bad.. yet.

 

[treserious]

Uh-huh.

I'm a believer in keeping speakers original - i.e. repairing the original drivers. Once the surrounds are shot, you can't use the speaker anyway. To me it's like saying "Yeah, that classic car with the 4 flats, if you replace those tires it won't run like it did originally."

yup, agreed.

this is whats known as the "dupe and upsell"

better profit margins in selling replacement drivers, that doing a refoam.


you must keep in mind that a refoam will yield better results than outright replacing the driver, unless original drivers from the manufacturer can be obtained.
but as many have pointed out, if the company no longer exists, then replacement parts are in the realm of "unobtainium"

 

[spkrdtr]

Has no one here actually measured a refoam product and then compared it back to a published spec?
DC

I do. Every refoam job I do for a customer comes with a WT report to show the customer exactly how it is performing after the repair. When published specs are available for a woofer I check to see how close the refoam job came. Below is a link to a site with woofer specs that may or may not be accurate (be warned, site is editable by visitors similar to Wikipedia).

http://www.thielesmall.com/database.asp

JBL also has tabulated specs for many of their woofers (attached).
If you have a WT kit (sold at Parts Express), all the better to check your work. You can also get pretty close to measuring a refoamed woofer's Fs using a function generator and a VOM.

Below is a link to a similar discussion about surrounds. Post #8 is mine and deals with the difficulty first time DIY'rs have identifying which surrounds to get for their repair job due to the foam industry's unwillingness to share compliance specifications.
http://www.audiokarma.org/forums/showthread.php?t=185214&highlight=surround+compliance

 

[Dynacophil]

Hi all,

My local speaker repair shop refuses to sell refoam kits, claiming that the process degrades the sound of the speakers too much.

If it is so, compared to rotten surrounds, why not everybody forces foam-surroundrotting....

 

[dc270]

Very Well Done spkdr!!

How close do you come to specs? Can you offer examples?
DC

 

[NYListens]

yup, agreed.

this is whats known as the "dupe and upsell"

better profit margins in selling replacement drivers, that doing a refoam.


you must keep in mind that a refoam will yield better results than outright replacing the driver, unless original drivers from the manufacturer can be obtained.
but as many have pointed out, if the company no longer exists, then replacement parts are in the realm of "unobtainium"

I like your analogy. I have refoamed 10 or so woofers now and each one sounded great afterward. IMO, refoaming (in most cases) is a very easy and not too time consuming a process. Furthermore, I doubt that a woofer's spec's are any more out of spec after a refoam then they are after say 5-8 years of service.

 

[spkrdtr]

Very Well Done spkdr!!

How close do you come to specs? Can you offer examples?
DC

Here's one attached of an AR3a woofer refoam. Fs was 17.9 hz. That's a fresh refoam with no break in. It will drop a hz or 2 after initial break in.

Original 3a ceramic woofers ran in the range of 15-20 hz. Real vintage AR Alnico woofers with supple cloth spiders and surrounds a bit less.

 

[gkimeng]

Has no one here actually measured a refoam product and then compared it back to a published spec?

Probably beyond the capabilities (or at least, the facilities) of the average DIYer and even many repair shops. We would hope the folks who sell refoam kits have done it, but (a) even if they say they have, we have only their word for it, (b) if the original manufacturer doesn't provide the specs for the driver or didn't provide them and is now gone and can't, you have nothing to compare to, and (c) haven't we all seen for ourselves that two speaker systems that have the same or very similar published specs can often sound quite different?

Published specs are great to have, but if exact matches in sound are the ultimate goal, there is probably still no instrument that can match educated ears with long experience. I'd take Ken Kantor's opinion of the result of my AR-3a refurbishment over the readout of a spectrum analyzer any day. Unfortunately, I don't have either available to me.

 

[Zilch]

Did someone say, "Measure?"

I get close, but rarely spot on, Fs typically higher, as much as 15 %.

I've never had a 116A/H refoam to original Fs of 28 Hz.

Finally, I broke down and bought a pair of expensive factory cone kits, primarily to find out if even THEY performed like that.

Are these worth a $172 recone job, EACH? Not in MY lifetime, they're not, nope, and certainly not while I'm sober.

Factory authorized speaker guy couldn't get them to fit, so the whole works is going back to JBL for THEM to make work now.... :