Yep, just about to write that.
I fixed at least one 15W like that before, but they have other corrosion issues at that point usually.
Under the lead VC glue junction is where it is and you're explanation makes sense.
Actually SS woofers corrode in general.
The rubber oxides, you can even see it in madisound pics.
I told that to a guy I was going to buy some 26W's from.
I said: "$50 less because you already have corrosion inside the magnet hole in the back".
He said: "no" and he did me a favor.
I still talk to him sometimes and think, wow, I wonder if I have the same psychological issues (common in "audiophiles")
Ever wonder why old woofers and current well thought out woofers, i.e. HiVi, have zinc coatings?
Also you shouldn't cut cones, then put glue in the gaps and then to make it even worse keep the paper cones uncoated.
You're solving problems and creating bigger problems by doing that, in my humble opinion, as they say on here.
Typical in EU and commonwealth countries AKA western culture, actually.
They "solve" problems by making bigger problems (usually at a scale that boggles the mind) and then go "look at me, I'm so smart, I 'fixed' it".
Also why are the frames so thin?
Put some SB Acoustic frames on those $300+ woofers.
I guess they got the Illuminators right.
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Aluminum and copper react, it is called galvanic corrosion, which is entry level stuff.
They should have taken care about that.
We use brass terminals here (zinc or nickel chrome plated at times), one side is copper, the other side is aluminum conductor... brass is relatively neutral to both.
The galvanic corrosion causes the material to be reduced to powdery oxide, moisture accelerates the reaction, so a covered joint lasts longer, if you are forced to use it.
As suggested above, a crimped joint may be more durable, thin brass tube (old ball pen cartridge / similar, or terminal) may work well enough.
Salty seaside air is even more corrosive in such cases, particularly in tropical climates.
They should have taken care about that.
We use brass terminals here (zinc or nickel chrome plated at times), one side is copper, the other side is aluminum conductor... brass is relatively neutral to both.
The galvanic corrosion causes the material to be reduced to powdery oxide, moisture accelerates the reaction, so a covered joint lasts longer, if you are forced to use it.
As suggested above, a crimped joint may be more durable, thin brass tube (old ball pen cartridge / similar, or terminal) may work well enough.
Salty seaside air is even more corrosive in such cases, particularly in tropical climates.
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I'm pretty/very cognizant of galvanic corrosion (or corrosion in general) whenever I am doing something.
I don't recall if that occurred to me when fixing SS woofers.
If I bought drivers out of the EU I guess I would buy Eton drivers/woofers with HEX cone.
Second speakers I built were with Eton 8-800, great woofer.
Usher has excellent build quality, SB acoustics also.
ScanSpeak has great bass extension, wide range, SPL and FR, build quality is great, but corrosion issues.
Best speakers for the money would be HiVi, maybe Tymphany.
SB acoustics for build quality, maybe Usher.
Dayton is great too.
I always wondered why "classic" SS woofers looked like Usher woofers/tweeters and then Joe D'Appolito, the MTM guy, told me they are made with Chinese parts and glued together in Denmark.
He said he worked as a consultant for Usher and they measure the best on a Klippel, which makes sense.
Why not just buy them from China (Usher)?
I don't know if Usher still sells drivers to hobbyists actually.
I don't recall if that occurred to me when fixing SS woofers.
If I bought drivers out of the EU I guess I would buy Eton drivers/woofers with HEX cone.
Second speakers I built were with Eton 8-800, great woofer.
Usher has excellent build quality, SB acoustics also.
ScanSpeak has great bass extension, wide range, SPL and FR, build quality is great, but corrosion issues.
Best speakers for the money would be HiVi, maybe Tymphany.
SB acoustics for build quality, maybe Usher.
Dayton is great too.
I always wondered why "classic" SS woofers looked like Usher woofers/tweeters and then Joe D'Appolito, the MTM guy, told me they are made with Chinese parts and glued together in Denmark.
He said he worked as a consultant for Usher and they measure the best on a Klippel, which makes sense.
Why not just buy them from China (Usher)?
I don't know if Usher still sells drivers to hobbyists actually.
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The timeline or history of this is not quite correct. Scans speak developed the (now “classic” line) woofers between the periods of 1978 to 1984. The cone supplier was Dr. Kurt Mueller. This company just recently celebrated their 100th anniversary.
http://www.kurtmueller.com/ (Germany)
Usher (Taiwan) came a lot later and were considered far east knock-offs of the Scan-Speak drive units, with the same rough slurry air dried cones. Its unclear whether they were from DKM or a build house on China. Usher made changes/refinements to the woofers including bigger spider, and initially were priced VERY low, compared to the Danish product.
Whether the raw materials were sourced from China ( or Germany ) it is hard to know but for sure it was assembled in Taiwan. I visited Usher in Taipei in early 2000s (my spouse is Taiwanese)
Many of these things were considered trade secrets in the present time and only discovered a lot later. Hence its easy to get the record mixed up.
http://www.kurtmueller.com/ (Germany)
Usher (Taiwan) came a lot later and were considered far east knock-offs of the Scan-Speak drive units, with the same rough slurry air dried cones. Its unclear whether they were from DKM or a build house on China. Usher made changes/refinements to the woofers including bigger spider, and initially were priced VERY low, compared to the Danish product.
Whether the raw materials were sourced from China ( or Germany ) it is hard to know but for sure it was assembled in Taiwan. I visited Usher in Taipei in early 2000s (my spouse is Taiwanese)
Many of these things were considered trade secrets in the present time and only discovered a lot later. Hence its easy to get the record mixed up.
It gets confusing at times, does it not, knock-offs made in Far East vs. branded made in Far East, sometimes in the same compound?
It is better to check out the actual build quality and buy those, but in an increasingly on line world, it gets difficult to judge.
And as above, even the famous ones are not quite as good as they should be.
So I stick to local, or flea market.
At least they can be fixed easily, we have three shops rebuilding speakers here in my city, and at least three speaker manufacturers in my city.
They all seem to be sourcing hand made or pressed cones from Jaipur, which has a centuries old tradition of hand made paper making.
So it boils down to the quality of parts, and quality of workmanship.
Philips and Bolton, both large scale speaker makers here, closed down long back, reputed speaker makers are thin on the ground here in India.
By the way, my city and suburbs have 5.24 million people, more than Chicago or Vancouver, to put things in perspective. That figure is from a Wikipedia article, not the most authentic source, but close enough that somebody took the trouble to write it up.
It is better to check out the actual build quality and buy those, but in an increasingly on line world, it gets difficult to judge.
And as above, even the famous ones are not quite as good as they should be.
So I stick to local, or flea market.
At least they can be fixed easily, we have three shops rebuilding speakers here in my city, and at least three speaker manufacturers in my city.
They all seem to be sourcing hand made or pressed cones from Jaipur, which has a centuries old tradition of hand made paper making.
So it boils down to the quality of parts, and quality of workmanship.
Philips and Bolton, both large scale speaker makers here, closed down long back, reputed speaker makers are thin on the ground here in India.
By the way, my city and suburbs have 5.24 million people, more than Chicago or Vancouver, to put things in perspective. That figure is from a Wikipedia article, not the most authentic source, but close enough that somebody took the trouble to write it up.
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And to be honest, the environment in Denmark is VERY different to Australia. Unless their transducers are marine certified for boat use, I don't expect them to last.
Australia is megadiverse (great biodiversity and climatic conditions), from the desert in the centre, tropical rainforests in the north and north-east, to mountain ranges in the south east.
Where I'm currently living, there's a well known saying "nothing lasts long in the Northern Australia" The climate is extremely harsh.
But only the locals know that.
Don't buy "that barbecue"
Don't buy "that lawnmower"
Don't buy "leather shoes"
"Keep the fans on if you leave the house for a few days"
All my wood working tools are kept indoors. Don't put them in the shed; they will turn to rust.
My speaker cabinets which had mitre joints had mould...
My kids go to school and each classroom has a refridgerator for kids to put their lunch in.
No one would dare leave their lunch at 30+C and 90% humidity for 4 hours in their bag, otherwise you'd be eating mould.
Australia is megadiverse (great biodiversity and climatic conditions), from the desert in the centre, tropical rainforests in the north and north-east, to mountain ranges in the south east.
Where I'm currently living, there's a well known saying "nothing lasts long in the Northern Australia" The climate is extremely harsh.
But only the locals know that.
Don't buy "that barbecue"
Don't buy "that lawnmower"
Don't buy "leather shoes"
"Keep the fans on if you leave the house for a few days"
All my wood working tools are kept indoors. Don't put them in the shed; they will turn to rust.
My speaker cabinets which had mitre joints had mould...
My kids go to school and each classroom has a refridgerator for kids to put their lunch in.
No one would dare leave their lunch at 30+C and 90% humidity for 4 hours in their bag, otherwise you'd be eating mould.
So, which commercially made speakers are durable in Northern Australia?
Japanese brands, or American, or even the Australian made speakers, do they last years?
I refer to the drivers, it seems even the wood is subject to attack by various organisms...
Comments from members in similar climates in other countries are welcome.
Oh, and one more thing, experience of those using marine or car speakers in the house under harsh conditions, that is also welcome, with details of the cabinet material.
Japanese brands, or American, or even the Australian made speakers, do they last years?
I refer to the drivers, it seems even the wood is subject to attack by various organisms...
Comments from members in similar climates in other countries are welcome.
Oh, and one more thing, experience of those using marine or car speakers in the house under harsh conditions, that is also welcome, with details of the cabinet material.
Nothing lasts
Primare class A/B amplifier- dead (Following the repair, the technician stated, without hesitation, and unequivocally "You should leave your amplifier in a room with 24/7 air conditioning")
Weber Q cooking grill- rusted through (support rep stated "Oh, that's not unusual. We'll send you a replacement, free of charge")
Router bit- rusted
Garden shears - rusted
Reverse cycle Air conditioner - PCB dead (home for lizards/geckos)
Electric gate opener - dead (home for ants)
Leather watch band- mouldy
Wife's leather shoes- mouldy beyond repair; thrown away.
Nothing kills mould like alcohol.
I was ready for Covid with all my supplies of isopropyl alcohol...
Purifi is UV treated and water resistant. But forgive me for not leaving it out in the garden shed to check out that feature.
Primare class A/B amplifier- dead (Following the repair, the technician stated, without hesitation, and unequivocally "You should leave your amplifier in a room with 24/7 air conditioning")
Weber Q cooking grill- rusted through (support rep stated "Oh, that's not unusual. We'll send you a replacement, free of charge")
Router bit- rusted
Garden shears - rusted
Reverse cycle Air conditioner - PCB dead (home for lizards/geckos)
Electric gate opener - dead (home for ants)
Leather watch band- mouldy
Wife's leather shoes- mouldy beyond repair; thrown away.
Nothing kills mould like alcohol.
I was ready for Covid with all my supplies of isopropyl alcohol...
Purifi is UV treated and water resistant. But forgive me for not leaving it out in the garden shed to check out that feature.
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That's a great 2-way or NE180 or NE225 is awesome also.
18WU should be the "best" 2-way woofer out there or 15WU.
It has great high and low SPL performance. Great Frequency range also.
I remember correctly I had 2 -- 18WU -- 4ohm that were corroded and the 15wu also, but they weren't stored correctly, probably.
Actually the 18wu 15wu were pretty much okay. But the 15w they came with was corroded under the lead glue.
I think all the 18wu had was maybe a little tiny (normal for most drivers) tick from the motor at 20 Hz, sine wave.
18wu and 15wu were the best low volume woofers I have heard, probably high volume also. I think Troels stated this about the 18wu, more or less. "They don't lose grip on the music at low volume" was roughly what he said. Low volume is what I use/need.
Most of the money in speakers is your own time, in my opinion.
That's why it doesn't sometimes make sense to try to save on drivers.
If you want something that will last, is ported, but still has tight bass, has high sensitivity, and have a lot of room build something like this:
http://www.troelsgravesen.dk/HESintro.htm
or
https://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Mezzo Galactica.pdf
Pro drivers make sense to me if you have the room and want a big box.
They have been perfected/optimized over decades and have small light motors that are meant to be more or less abused.
That's just what Joe. D told me:
He worked as a consultant for Usher and ScanSpeak got the cones from China and/or Usher, if I recall correctly.
I think we were talking about the pulp cones.
Build what you "dig", who cares, right?
Zaph is my favorite speaker designer.
Dayton are some of the ugliest drivers; Eton are some of the best looking drivers.
But I couldn't disagree with his aesthetics more.
15w and 18w measure better than 18wu, so they are better.
Not even close, they might do some things "better".
Also nonlinear distortion measurement graphs are probably indirect testing of a good driver design.
As in, they are a sign the driver does other things well.
I didn't go with the Dayton RS52 vs TC9 because the RS52 has better nonlinear distortion, although the graph is smoother and maybe slightly better in some places.
I went with the RS52 for the same reason people go with the 18wu vs the 18w.
Well one of the reasons.
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Just to add some photos to this thread. I'm about to fix a second driver, the first one is sitting my Zaph 2 way, running nicely.
Here is a photo of the corrosion at the failure between the VC copper lead and the tinsel.
There's clearly some chemical reaction between the glue and the VC copper wrap-around solder joint to the tinsel.
The green oxidation is clearly apparent too. Disregard the VC copper break in the photo - that was done with the scapel while exposing the joint.
The powder from the corrosion spills out when the scapel reveals the joint, just like the blood from a corpse in The Andromeda Strain except not red.
I very carefully unwind a turn on the VC and re-thread it through the yellow support basket and I'm pretty meticulous in my solder reapair, using P1000 wet and dry very carefully to remove laquer from the copper and also use flux and 60/40 lead solder etc. with a reasonably good iron (Hakko 888D).
Then anchor at same site with glue gun and refit the cone etc. Use a 50Hz signal from the phone to confirm centre, leave vertical overnight.
I've only ever done one repair (it shows! not pretty but fully functional) shown below - used desolder braid - works fine.
Here is a photo of the corrosion at the failure between the VC copper lead and the tinsel.
There's clearly some chemical reaction between the glue and the VC copper wrap-around solder joint to the tinsel.
The green oxidation is clearly apparent too. Disregard the VC copper break in the photo - that was done with the scapel while exposing the joint.
The powder from the corrosion spills out when the scapel reveals the joint, just like the blood from a corpse in The Andromeda Strain except not red.
I very carefully unwind a turn on the VC and re-thread it through the yellow support basket and I'm pretty meticulous in my solder reapair, using P1000 wet and dry very carefully to remove laquer from the copper and also use flux and 60/40 lead solder etc. with a reasonably good iron (Hakko 888D).
Then anchor at same site with glue gun and refit the cone etc. Use a 50Hz signal from the phone to confirm centre, leave vertical overnight.
I've only ever done one repair (it shows! not pretty but fully functional) shown below - used desolder braid - works fine.
And just to add - apart from this defect, I really like the drivers. The rest of the engineering + build on them is excellent and I'm very pleased with their performance. Has put a bad taste in my toolbox re: next build though. Has ScanSpeak ever come clean on this? Proven it's fixed and was a Friday arvo job?