JBL Century L100 Restoration Project

[Greg Roberts]

Hi all,

I just took on another JBL speaker restoration project and I thought I would share it with the forum. It's been years since I documented a speaker restoration, so I hope you enjoy the photos and check out some of the new techniques I'm using now. I welcome your comments as this project progresses.

As of right now, I have just received the speakers and I've done my initial inspection, noting the cosmetic issues and general condition of all the parts. I provided my customer with detailed notes of what I found, and also a general outline of the restoration work that I recommend to be done. He's given me the green light to proceed!

Here's a link to the restoration webpage if you'd like to see all the photos www.klipschupgrades.com/centuryrestoration.shtml

Greg

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[grumpy]

Should be an interesting set of restoration choices! At least most of the drivers appear to be intact.
Thanks for electing to document the process.

[Ed Zeppeli]

Yep. I'll be following along!

Good luck,

Warren

[martin2395]

Wouldn't it be better to make a 1:1 copy of the cabinets and transfer the parts? :dont-know:

[BMWCCA]

I checked out the links to your previous restorations and your work is very impressive.

Craftsmanship and detail are fantastic, I only wonder what value the L100 will have once completed in non-stock form such as your previous projects and what the end result must have cost the owner! Nothing against your work but I'm sure you don't work for free and the finished custom L100 will still sound like an L100!

Can't wait to see how you resurrect this pair. :cheers:

[SEAWOLF97]

I only wonder what value the L100 will have once completed in non-stock form such as your previous projects and what the end result must have cost the owner! Nothing against your work but I'm sure you don't work for free and the finished custom L100 will still sound like an L100!



I do agree with Phil. And don't understand why someone would pay to have L-100's restored ? They are not a high value model and can be found in fine shape for ...I'm guessing ...less than buying this pair plus the restoration cost. The only way it makes sense to me is if there is sentimental value somewhere in the mix.

With the number of scavenged L-100's out there, I've seen and am somewhat sure that there are a lot of empty cabs to load with these drivers.

Plse. don't take offense. I'm just not following the reasoning. :dont-know:

[Greg Roberts]

Hey guys,

No offense taken. I completely understand the questioning about the cost of doing such a project. I am straight up with my customers right from the start, and I make sure to tell them that of all the restorations I've done, not one of them had a cost that was at or less than the value of the speakers on the open market - and in fact most of them end up at several times the cost of the market value. It has to be done as a labor of love, and for sentimental reasons. Perhaps my customer will chime in here and tell us why he is willing to spend the money on this project.

Let's not make him be defensive though - he obviously has his reasons for spending a couple of grand to make these into better than new condition. It's really not for us to judge him.

A couple of thoughts I have about it. First off, even though there may be other used cabinets out there that the parts could be put into, it doesn't mean those cabinets are not without some problems. If someone wants perfect, new looking speakers, they will have to have new veneer. If someone wants a custom veneer and finish, they'll need new veneer.

So then, what about the cost of restoring these old cabinets to like new condition versus making new cabinets? Certainly a valid question and one that I've given a lot of thought to. The fact is, even with extensive repairs, I have found that restoring old cabinets is still less time consuming than building new ones. I know they are simple boxes, but by the time I cut the pieces, assemble them, and then router out the fronts and backs for the components, I'll be right at the same time or longer than fixing old cabinets.

I worked on the speakers some today, so pics will be coming soon.

Greg

[hjames]

Very cool Greg, I'm not a big fan of the L100 system, but a restore/refurb of any older JBL is interesting.
Thanks for keeping us in the loop, and good luck!



Hey guys,

No offense taken. I completely understand the questioning about the cost of doing such a project. I am straight up with my customers right from the start, and I make sure to tell them that of all the restorations I've done, not one of them had a cost that was at or less than the value of the speakers on the open market - and in fact most of them end up at several times the cost of the market value. It has to be done as a labor of love, and for sentimental reasons. Perhaps my customer will chime in here and tell us why he is willing to spend the money on this project.

Let's not make him be defensive though - he obviously has his reasons for spending a couple of grand to make these into better than new condition. It's really not for us to judge him.

A couple of thoughts I have about it. First off, even though there may be other used cabinets out there that the parts could be put into, it doesn't mean those cabinets are not without some problems. If someone wants perfect, new looking speakers, they will have to have new veneer. If someone wants a custom veneer and finish, they'll need new veneer.

So then, what about the cost of restoring these old cabinets to like new condition versus making new cabinets? Certainly a valid question and one that I've given a lot of thought to. The fact is, even with extensive repairs, I have found that restoring old cabinets is still less time consuming than building new ones. I know they are simple boxes, but by the time I cut the pieces, assemble them, and then router out the fronts and backs for the components, I'll be right at the same time or longer than fixing old cabinets.

I worked on the speakers some today, so pics will be coming soon.

Greg

[BMWCCA]

It has to be done as a labor of love, and for sentimental reasons.
I completely agree.

I've known several friends who've sunk close to $100,000 restoring cars that might be worth $20k in excellent original condition. The restorers were craftsmen chosen by the owners for their attention to detail and trusted them with their treasures. No way to justify such an expense except to say they love what they have and want to keep them forever.

The problem comes when a couple does this and then gets divorced. When they come to me to establish the value for their completed project as part of the property settlement, they don't like the truth. I usually send them to the restorer who took their money in the first place!
;)

[Greg Roberts]

Update. The components have been removed, the cabinets initially sanded, and initial epoxy repairs.

Lots more photos and commentary on the website http://www.klipschupgrades.com/centuryrestoration.shtml

Greg
6515965160651616516265163

[Greg Roberts]

Couple more pics6516465165

[Ed Zeppeli]

That's great. I checked out your link. Thanks for sharing and please keep updating here as you update there.


Regards,

Warren

[fpitas]

Cool project. Not sure what you plan for the crossover restoration, but Troels Gravesen did some interesting work:

http://www.troelsgravesen.dk/JBL_L100.htm

Francis

[Greg Roberts]

Thank you for that link. I think he did a thorough job with this crossover upgrade.

I'm not sure what we're going to do yet.

Greg

[Mr. Widget]

Thanks for sharing... please keep it coming. Beautiful work and amazing documentation. I've done a few projects and my work was pretty good, but I positively fail when it comes to documentation. I get on a role and plow on through never stopping to record what I've done.

I'm sure your work will be informative and inspirational for many.


Widget

[Wagner]

I too "remember now why the name VOLTI rings a bell"

http://www.audioheritage.org/vbulletin/showthread.php?4353-Hi-from-a-new-member&p=41408&highlight=#post41408
http://www.klipschupgrades.com/jbl4311.shtml

Things must be slowing down in "Maximumawambiaklipschornzania"

[hjames]

Greg is sharing good stuff here ...
let THIS thread stand on its own merits.

There is NOTHING to be gained by bringing that mess up again,
lets leave that flamefest be ...

I'll delete this post Thurs PM

But its not just Volti - there have been a NUMBER of interesting restoration threads
Greg has been involved in at this site, plus I've seen some other cool threads he's posted on the web.
Disclosure - I have never bought anything from him, but I've met him at a couple local Audiofests
and he is an enthusiastic and friendly guy. His speakers look and sound really good.

But for some reason, some folks seem inclined to attack him for whatever motivates them.
Don't know if its boredom, if they are jealous of his skills, of his prices, or of something else.
But whatever it is, their attacks have been WAY out of proportion for "welcoming" someone to the site.

The guy has a business, and it seems like he has no shortfall of customers willing to hire him for the kind of work he does.
Lets keep letting him share the new thread here and not dredge up old trash ....

And yes, there WERE some constructive complimentary posts in that flamefest -
but the anger and venom really make it a tough read. Its not something I'd recommend to an outsider.
Its all the basement troll stuff the internet is famous for - people saying things they would NEVER say face to face.

Not sure why discussions can't be kept at a civilized level without all the loaded words, insults, and attacks.
Attacking me or this post won't change that - it just proves the truth of this all.

[Wagner]

Greg is sharing good stuff here ...There are dozens of threads on this site, by and about members resurrecting badly damaged JBLs (THEIR OWN SPEAKERS) and doing it purely for the love of the speaker and all things JBL, not soft selling their services (and a hell of a lot more interesting, involved and challenging than this primer level remedial patch job) You think someone treating us to yet another photo essay on smearing epoxy and Bondo on old damaged cabs and the inevitable re-veneering is "good stuff" then maybe it's you that are suffering from "boredom, jealous of his skills, of his prices, or of something else". There are masters inhabiting this place (JBL systems and building masters, both boxes and networks) that have documented projects that make what Greg Roberts does look like them trimming their finger nails..........and for a whole hell of a lot less money (again, they do it for sheer love and respect of the moniker's history, innovations, performance and standing). Other than it IS nice to see older Heritage models well preserved (and resurrected), on the scale of interest, that scale running from 0 to 10 I'd put this effort at about a 1.25 (and I only give it that as I was able to learn what the "I tune 'em by ear" "artist" Greg Roberts uses in epoxies) :banana:
The guy has a business, and it seems like he has no shortfall of customers willing to hire him for the kind of work he does.Lets keep letting him share the new thread here and not dredge up old trash ....Yes, he does. So let him pay for his advertising and not promote it here on an audio forum free of charge with his "low key" "easy going" trolling for customers technique, same as he has exploited subliminal marketing over at the Klipsch forum for ages now. Don't know why you "seem" to think he has "no shortfall of customers"; if that were the case he wouldn't be here now casting his net for hopeful commissions. This site really should charge a fee for those peddling their wares (engaged in commercial enterprise) with post counts less than 50 in 10 years and who clearly could give a shit about a JBL other than it's a piece of wood they might be able to make a buck off of.

[JeffW]

Thanks for sharing... please keep it coming. Beautiful work and amazing documentation. I've done a few projects and my work was pretty good, but I positively fail when it comes to documentation. I get on a role and plow on through never stopping to record what I've done.

I'm sure your work will be informative and inspirational for many.


Widget

Made it a whole page before it got dumped on.

[Mr. Widget]

Greg is sharing good stuff here ...
let THIS thread stand on its own merits.

There is NOTHING to be gained by bringing that mess up again,
lets leave that flamefest be ...

I'll delete this post Thurs PM

But its not just Volti - there have been a NUMBER of interesting restoration threads
Greg has been involved in at this site, plus I've seen some other cool threads he's posted on the web.
Disclosure - I have never bought anything from him, but I've met him at a couple local Audiofests
and he is an enthusiastic and friendly guy. His speakers look and sound really good.

But for some reason, some folks seem inclined to attack him for whatever motivates them.
Don't know if its boredom, if they are jealous of his skills, of his prices, or of something else.
But whatever it is, their attacks have been WAY out of proportion for "welcoming" someone to the site.

The guy has a business, and it seems like he has no shortfall of customers willing to hire him for the kind of work he does.
Lets keep letting him share the new thread here and not dredge up old trash ....No need to delete... you're making a valid point.

Just the other day I was commenting on how the members of this site have been less inclined to toss grenades at each other than in years past. I thought perhaps it was due to a maturing internet where we've learned how to interact. I guess not.



Widget

[hjames]

So let him pay for his advertising and not promote it here on an audio forum free of charge with his "low key" "easy going" trolling for customers technique, same as he has exploited subliminal marketing over at the Klipsch forum for ages now. Don't know why you "seem" to think he has "no shortfall of customers"; if that were the case he wouldn't be here now casting his net for hopeful commissions. This site really should charge a fee for those peddling their wares (engaged in commercial enterprise) with post counts less than 50 in 10 years and who clearly could give a shit about a JBL other than it's a piece of wood they might be able to make a buck off of.

The more restoration threads the better - its how people learn about what craftsmen do.
People posting clear pictures and discussions about how they do things is what makes this site useful
Let people make up their own minds about the quality or caliber of the work without rants from the sidelines.

My only point here is just to say relax, keep things civil, act like adults.

The last time I checked, there is no charge for folks to post here -
not sure why you feel its your place to recommend charging some folks.

If you really feel the site needs the money,
when was the last time YOU donated any money to the Lansing Forum?
Click the GREEN word DONATE in the grey bar towards the top of the page.

[svollmer]

I was wondering how long it would take before he put 2 and 2 together.

Greg: please don’t be put off by some here. Many of us love looking at pictures of restorations and appreciate the time it takes to document them and post them for others to learn from or just enjoy.

Keep ‘em coming, and thanks!

[Greg Roberts]

There are some mean people in the world. I don't let it put me off. There are a hundred times more good people, so it's not difficult to avoid the bad ones. It is hard sometimes to tune out their hateful words, but it can be done. Takes a strong mind.

Over the years I've had countless people email to tell me how much they've enjoyed looking at my restoration threads. Many people have found the information to be helpful for their own projects. It's been a long time since I've documented a restoration, and there have been many improvements in the techniques that I employ with these restorations that I will document on this one. So I think this new information will be good for many people to see and learn from.

More pics coming soon.

Greg

[Wagner]

The last time I checked, there is no charge for folks to post here -
not sure why you feel its your place to recommend charging some folks.
If you really feel the site needs the money,
when was the last time YOU donated any money to the Lansing Forum?
Click the GREEN word DONATE in the grey bar towards the top of the page.

Funny
"ha ha"

"Toss grenades", "mean people"............how silly is that? I call what I have written simply speaking the truth of the matter
And I don't think you need to worry about "Greg's" feelings; after all he's getting fairly broad exposure and advertising in front of a group of enthusiasts that are some of the most likely to be in the market for cosmetic restorations as there ever will be...................and all for "free" (only the time it took him to make a few posts and take a few "pics")

But you are correct, there is no "charge" to post (and I did not suggest that there be one, OR that there was one, so please refrain from misquoting me and putting your all too familiar "out of context" and condescending spin on things with your little lectures)
I only suggested that there should be a minimum participation requisite BEFORE one starts hawking their wares, be it a hard (direct and honest) or "soft" sell

It seems to be the norm now at every Audio forum I visit; 25-50% of the "posters" ("members") are there only to try and sell something

Tell you what I will do; anyone withing driving distance of me that has a pair of cabs (L100 class or smaller) that are in need of some "love", bring them to me and I will do them at NO CHARGE other than YOU (the owner) pay for all materials involved. Unload the boxes and drop them off, that's it.
My current health situation precludes me from being able to do veneer work (I'm currently working with only 1 and 1/2 hands at the present) but scratches, stains, chips, marks, crushed corners, installation of grille cloth etc......................all of those are still well within my current purview
I can and will also do any re-capping you desire to your specifications (re-capping, NOT design or scratch building unless you have a kit you want assembled)

Aside from my physical limitations, my philosophy always has been and always will be to restore and preserve these well traveled examples, whenever possible, to as close as they were on the day that JBL made them...................never been a big fan of ugly ass Bubinga and Zebra type veneers on JBLs anyway..............so I guess you can now call me an unsophisticated boor as well

We can even discuss woofer re-edging (some drivers I am reluctant to do for others)
Again, YOU pay for any and all materials (and handle all procurement and ordering of parts) and that's it; I'll take care of the rest

If you are skeptical of my abilities and skill, I have an example here of my work for your approval

My only requirement is that YOU (the owner of the boxes) take any "before and after" shots if you want them and that we give it a few more weeks for things to warm up as a great deal of this work is done out back AND all finishes and adhesives work better at 70 degrees or better (I work Bill LeGall style/Miller Sound; on my back deck for the dirty stuff)

And NOT be on some explicit, time sensitive schedule. I will be leaving soon to visit my Son at Fort Stewart; so I would suggest my turn around for you would be at best a month, give or take.........but hey, it's FREE! (in other words, for now, don't bring me something you have or need to have back in a week)

How's that sound?

[Mr. Widget]

It seems to be the norm now at every Audio forum I visit; 25-50% of the "posters" ("members") are there only to try and sell somethingAnd that's a problem? We all buy stuff and many of us also occasionally sell stuff too...

If the OP wants to make an infomercial we can tune out when it ceases to entertain. I'm not sure he is, but even if his goal is to drum up business I don't see a problem there. He, and every member here, is also free to place an ad in one of the two Market Place areas.

As for your generous offer to give some love to Forum Members' bookshelf speakers. I have a pair of L100s that are as they were the day I bought them from a second hand store. They could certainly use some love. I wish I could take you up on your offer, but the drive from SF is a bit much.


Widget

[Doc Mark]

Good Morning, Greg,

I just stumbled upon your L100 restoration thread, and I'm very glad to have done so! As others here have already said, your work is first-rate, and I'm very impressed with the care and fine details you are showing in your documentation of all the work! Please keep it coming, as I assure you that the vast bulk of the LH membership are enjoying this just as much as I am!!! As to why your customer would want this to happen, well, that's easy for me to imagine. If he and these speakers have a "history" together, then why would he NOT want "his JBL's" to be tenderly and carefully restored to their former glory, and even better than new?! Works for me! Thanks, again, for sharing your work, and I eagerly look forward to following your journey on this excellent JBL adventure!! Well done, Sir! Take care, and God Bless!

Every Good Wish,
Doc

[SEAWOLF97]

never been a big fan of ugly ass Bubinga and Zebra type veneers on JBLs anyway...........

While I love the looks of those woods, a little goes a long way for me. The entire side of a large speaker done in it seems "too busy/distracting" . Oak/Walnut seem better for large areas. JBL knew what they were doing when producing those products.

I appreciate a beautiful cab as much/more than others. Black vinyl wrapped boxes s/b illegal (IMHO)

It does seem that one strident poster here wants to assert their rules/position on the group , while the mods actually maintain cooler heads ... :dont-know:

[hjames]

It does seem that one strident poster here wants to assert their rules/position on the group , while the mods actually maintain cooler heads ... :dont-know:

All I asked for was civility and common courtesy, and hardly strident
- seems like you and Wagner are the only ones in "the group" who disagree.
I think most members would agree that civility and common courtesy should be a basic rule in any web forum that wants to keep members.

This forum has served a useful purpose to a lot of the folks here,
and keeping it civil goes a long way towards it staying relevant and vibrant.

So when someone like Greg starts a thread to archive his steps in restoring one of the more popular JBL models,
it kinda makes sense that it stay open and friendly. And that folks keep personal attacks out of it.

Why do I have to defend asking that we keep the Lansing Forum a friendly and open place??
Why are we even having to discuss this, and distracting from the basic point of this thread?

I'm not playing tag-team replies with either of you - further digressions are pointless.
Take it up with the mods if you really feel I am a threat to you.

[Wagner]

It does seem that one strident poster here wants to assert their rules/position on the group , while the mods actually maintain cooler heads ... :dont-know:

Thank you for your thoughtful consideration of my my words; refreshing to say the least

Not trying to assert anything on anyone; just stating my honest perspective based on what I can see and the history of it all............everyone today talks much about "community"; well, I've made what I feel is a right fair alternative offer to the community, a "FREE", "no risk" alternative, and for that I am harshly rebuked

Not just criticizing for the sake of it (or as one poster so eloquently, and "civilly", articulated it "crapped" on) and to demonstrate that fact have offered, again, an alternative involving no financial benefit or reward of any kind for myself to validate that fact; on the contrary, TIME is the most generous gift one can give to a fellow Human being, and once given that's it

One that I sincerely believe is true to the title "Lansing HERITAGE" (I take that seriously enough to offer my services in the form of volunteer work) in an attempt to try and help preserve it in some small way, especially for someone who's finances are "limited" (which would be the ideal), but who's motives are sincere (love for the make's history, beauty and inherent quality and not the resale value or "status")

Sorry if any of you in "the group" find a negative motive or angle in that

Best wishes to all

[Greg Roberts]

First coat of epoxy is sanded and second coat applied. Many more photos and details at the project webpage http//:www.klipschupgrades.com/centuryrestoration2.shtml

I talked to my customer on the phone yesterday and he mentioned that he was reading the comments on this thread. He told me that this was definitely a labor of love for him. He's had these speakers for many years, through college and everywhere in between, and so he's very happy to finally be able to bring these speakers back to new, or even better than new condition. He'll be enjoying these for many years to come. He knows he could buy L100 speakers in decent condition and for a lot less money than this restoration is going to cost, but they wouldn't be "his" speakers, and they wouldn't have Rosewood veneer, cane grills, wood trim on the fronts, upgraded crossovers, and be in perfect condition. He feels the money spent for these things will be money well spent. This is exactly why I'm in this business, and I'm happy to be offering this level of service to my customers.

More to come.

Greg

65196651976519865199

[SEAWOLF97]

He's had these speakers for many years, through college and everywhere in between, and so he's very happy to finally be able to bring these speakers back to new, or even better than new condition. He'll be enjoying these for many years to come.

Glad to know the motivation for the work. I'm sure the final product will be nice.

I had similar feelings towards a certain pair of mine. Ordered them unseen while in the War Zone and had delivered home. Enjoyed for many years and kept them in great shape.

Slowly the tweeter foam rotted and replacements were NLA. Highs disappeared. I tried to fix,but no joy.

Hated to see them just sitting while I had moved on to better things. Finally gifted them to a friend who had the resources to get them repaired (at prolly higher cost than the pair were .. new) . It was a somewhat sad day , as you can get emotionally attached to an "old friend".

[Wagner]

I talked to my customer on the phone yesterday and he mentioned that he was reading the comments on this thread. He told me that this was definitely a labor of love for him. He's had these speakers for many years, through college and everywhere in between, and so he's very happy to finally be able to bring these speakers back to new, or even better than new condition. He'll be enjoying these for many years to come. He knows he could buy L100 speakers in decent condition and for a lot less money than this restoration is going to cost, but they wouldn't be "his" speakers, and they wouldn't have Rosewood veneer, cane grills, wood trim on the fronts, upgraded crossovers, and be in perfect condition. He feels the money spent for these things will be money well spent. This is exactly why I'm in this business, and I'm happy to be offering this level of service to my customers.

More to come.

Greg



Really?

[Odd]

Really?

If you do not like this thread, why read it?

Me and many others think it is OK.


Lost job? Wife threw you out? Other problems?

[Wagner]

If you do not like this thread, why read it?

Me and many others think it is OK.


Lost job? Wife threw you out? Other problems?

http://forums.stevehoffman.tv/styles/default/xenforo/clear.pnghttp://forums.stevehoffman.tv/styles/default/xenforo/clear.pnghttp://forums.stevehoffman.tv/styles/default/xenforo/clear.png:blink:

[Mr. Widget]

http://forums.stevehoffman.tv/styles/default/xenforo/clear.pnghttp://forums.stevehoffman.tv/styles/default/xenforo/clear.pnghttp://forums.stevehoffman.tv/styles/default/xenforo/clear.png:blink:I'm afraid I had the same thoughts as Odd... I can't figure out why you are so unhappy with the thread. I'm not particularly interested in the restoration of these speakers, but I appreciate other people's interests and as I posted earlier, I am quite impressed with the documentation.


Widget

[Wagner]

I'm afraid I had the same thoughts as Odd... I can't figure out why you are so unhappy with the thread. I'm not particularly interested in the restoration of these speakers, but I appreciate other people's interests and as I posted earlier, I am quite impressed with the documentation.


Widget
I have no problems with the message, rather the motive
I thought I made that clear; guess not
I'll bow out now

On another note:
Let me know if you change your mind regarding your old boxes; weather will soon be ideal!

[macaroonie]

Wagner you really should put the ball down.

[Wagner]

Wagner you really should put the ball down.
I thought I had; this was not clear or substantive enough for you?:

I'll bow out now

[svollmer]

Greg,

Can you tell us more about the epoxy you are using? Brand and type? Thanks.

Steve

[Greg Roberts]

Sure. Here's a pic.

65209

I've heard good things about the "West System" products too, but when I did a search for a wood-restorative epoxy, I found it difficult to figure out exactly what to buy out of all their products. During my search, the "Smiths Fill It" brand popped up and I've been using it ever since. It's expensive, but I like the long pot life (90 minutes) and I get consistent results from it. I wait 24 hours before sanding (70 degrees).

http://www.smithandcompany.org/

My usual source, Jamestown Distributors, is currently out of it, but here's another place to buy it (website is a little cumbersome) https://secure.rotdoctor.com/12order-S.html

I buy the 2-pint kit and it does more than you think it would. I use quite a bit of this stuff, but a gallon would be too much for me, I think it would go bad before I used it all.

I've had good luck with premium body filler as well. I like the RAGE Gold, linked below. If I know I'm going to be covering it with veneer or a "smoothing panel" and then veneer, I will often just use this product.

http://www.amazon.com/Fibreglass-Evercoat-112-Premium-Lightweight/dp/B000P6URMA/ref=sr_1_2?ie=UTF8&qid=1429355110&sr=8-2&keywords=rage+body+filler (http://www.amazon.com/Fibreglass-Evercoat-112-Premium-Lightweight/dp/B000P6URMA/ref=sr_1_2?ie=UTF8&qid=1429355110&sr=8-2&keywords=rage+body+filler)

Greg

[Greg Roberts]

Epoxy is done now and the front trim is installed. Much more detail and more pics on the webpages

I'm heading out to Chicago for the AXPONA audio show where I'll be showing my Volti Audio Vittora speakers. So I won't be working on this project again until the first of May.

Greg652486524965250

[Greg Roberts]

Back from a very successful AXPONA show, and now I've got more work than I know what to do with.

But I've made some progress on this project, and so I've updated the webpage with images and text. A few images here.

My customer chose some beautiful Bubinga veneer that I had in stock, and these old cabinets are starting to look fine.

Greg

655506555165552

[Wagner]

Epoxy is done now and the front trim is installed. Much more detail and more pics on the webpagesI'm heading out to Chicago for the AXPONA audio show where I'll be showing my Volti Audio Vittora speakers. So I won't be working on this project again until the first of May. Greg65250The L100's front baffle was continuous out to the "edge" for a very specific reason (but I do seem to remember you saying you don't worry about those sort of things too much) Thanks to JBL's engineering and design efforts, as well as others, including notably Roy Allison, those chunky AResque front panels with sunken grille frames were eventually abandoned by most serious speaker designers (most are shooting for the benefits (ideal) of the "infinite" baffle here, in one form or another) I mean, why deliberately install in the form of a completely useless cosmetic feature the potential detriment of the very real possibility of adding edge diffraction and reflection issues to an already sonically "challenged" box as it is? Compounding sins with more of inclusion would hardly prove to make things "even better than new" I would think?
From the Lansing Heritage Library:


http://www.audioheritage.org/images/jbl/extracts/thumbs/4310bw_small.jpg (http://www.audioheritage.org/images/jbl/extracts/4310bw.jpg)JBL 4310 Illustrating Raised Oval Baffle for HF Drivers© Stereo Sound Publishing Inc. (Japan), Courtesy Koji Onodera



As a consequence, the design featured a grille frame configured with a regular oval, or racetrack, shaped cutout. This oval opening was closely fitted to a similarly-shaped wooden island fastened to the baffle panel. The transducers were, in turn, fastened to this oval island (with the woofer set in a recessed opening so that its front edge was flush with the surrounding mounting surface). The result was a configuration in which the transducers' propagation patterns "saw" only a flat surrounding baffle -- the grille frame having become, acoustically, part of an unbroken plane out to the edges of the enclosure. The effect of the necessary recessing of the structural baffle to accommodate the grille frame thickness was thereby nullified and any undesirable high frequency reflections that typically arise from the protruding enclosure edges were eliminated. (It should be noted that the cutouts in the side panels of the 4320 were done for the same reason.)

[mech986]

OTOH, if you read further down:

http://www.audioheritage.org/html/profiles/jbl/l100.htm

After some field experience with the 4310 and additional testing, it was found that the unique uninterrupted flat baffle treatment did not provide as significant acoustical advantages as had been supposed. Accordingly, the feature was dropped. The tweeter was replaced with a smaller diameter unit to increase high frequency dispersion and the crossover frequencies were modified to yield a smoother response. The subsequent version was given the model number 4311 and was built with a conventional recessed baffle and with the H.F. radiator raised to the acoustical plane of the low frequency driver and enclosure front edge.

[hjames]

Wow - just let go of the hate and please let the man continue his project without further interruptions.
Your constant attempts to put him down have gotten very tired.

Start your OWN thread with rebuttals if you like, but its incredibly RUDE when you keep jumping in like this.

And you don't have to attack me in response ... I'm just asking (again) for courtesy.



The L100's front baffle was continuous out to the "edge" for a very specific reason (but I do seem to remember you saying you don't worry about those sort of things too much) Thanks to JBL's engineering and design efforts, as well as others, including notably Roy Allison, those chunky AResque front panels with sunken grille frames were eventually abandoned by most serious speaker designers (most are shooting for the benefits (ideal) of the "infinite" baffle here, in one form or another) I mean, why deliberately install in the form of a completely useless cosmetic feature the potential detriment of the very real possibility of adding edge diffraction and reflection issues to an already sonically "challenged" box as it is? Compounding sins with more of inclusion would hardly prove to make things "even better than new" I would think?
[STUFF deleted]

[Wagner]

OTOH, if you read further down:

http://www.audioheritage.org/html/profiles/jbl/l100.htm

After some field experience with the 4310 and additional testing, it was found that the unique uninterrupted flat baffle treatment did not provide as significant acoustical advantages as had been supposed. Accordingly, the feature was dropped. The tweeter was replaced with a smaller diameter unit to increase high frequency dispersion and the crossover frequencies were modified to yield a smoother response. The subsequent version was given the model number 4311 and was built with a conventional recessed baffle and with the H.F. radiator raised to the acoustical plane of the low frequency driver and enclosure front edge.
Agreed: no matter what they did, they couldn't get the L100 to "work right" (as far as expectations) and yes, the simple (cheap) solution didn't work as well as planned, but the simple solution still added costs to making a box. That fact in and of itself (and specific model, the L100 project) doesn't negate the often misunderstood realities of baffle 'n' box reflection and diffraction issues. It is also worth noting that not too long after this time, the recessed baffle of old was pretty much abandoned altogether....................by JBL as well as countless others and remains the near design "standard" to this day for this class of box
It was as much the experimentation with baffle design as it was the existing joinery tooling and committing to a total switch over at that juncture of development of what was essentially a break through/break out design (my theory) Simple costs versus reward scenario:


After some field experience with the 4310 and additional testing, it was found that the unique uninterrupted flat baffle treatment did not provide as significant acoustical advantages as had been supposed.
Note "as significant acoustical advantages as had been supposed" which to my mind translates to "not enough to justify the additional labor and money" but certainly doesn't indicate there wasn't any (improvement)

Like I said, in context:

I mean, why deliberately install in the form of a completely useless cosmetic feature the potential detriment of the very real possibility of adding edge diffraction and reflection issues to an already sonically "challenged" box as it is? Compounding sins with more of inclusion would hardly prove to make things "even better than new" I would think?

[Greg Roberts]

A little more progress.

Here's the link to Page Three of the restoration

http://www.klipschupgrades.com/centuryrestoration3.shtml

Greg


65837

[audiomagnate]

...with post counts less than 50 in 10 years and who clearly could give a shit about a JBL...

OK now I'm upset. That should be "couldn't give a shit."

[Greg Roberts]

I've finished up this project now.

The bubinga veneer with cane grill cloth is a stunning combination.

I made a couple of small improvements to the crossover design and these speakers are sounding better than they ever have.

Right now I'm enjoying these in my living room, but I'll be packing them up and sending them back to my customer soon.

I've detailed this restoration in four webpages on my website, including detailed cost. Page 1 is http://www.klipschupgrades.com/centuryrestoration.shtml

Greg

[Wagner]

All that work
All that money

And they are still an asymmetrical pair

But you have managed (congratulations!) to make them (an industrial, historical icon, like 'em or not) look like a pair of custom dream Heresys, with all the "bubinga" wood and cane grille cloth

They're really big on ugly ass, "exotic" veneers over at the Klipsch forum..............at least they were a while back (I spent a little time there, long ago)

Not stuff like you "build" but just straight up veneer jobs on EVERYTHING; think it was requisite to joining that site (doing or having done some veneer project) Of course you are well aware of that and have taken it to a new level

Think you're missing out on some work however. The veneer of choice over at Klipsch still appears (after a cursory search) to be "zebrawood" not "bubinga"

https://community.klipsch.com/index.php?app=core&module=search&do=search&fromMainBar=1

https://community.klipsch.com/index.php?app=core&module=search&do=search&fromMainBar=1

[grumpy]

All that acidity...

Seems like they'd look right at home in an upscale retro office being driven by a restored SA-6xx integrated amp.
Hope the customer enjoys them for a long time.

[martin2395]

I think that it's a bit pity to make them look like old, plain AR boxes :(
But if the customer wanted them like that...

[Wagner]

All that acidity...

Seems like they'd look right at home in an upscale retro office being driven by a restored SA-6xx integrated amp.
Hope the customer enjoys them for a long time.

Sorry you interpret my comments, or attitude as "acidic"; not the case (not my intent) I am only speaking my honest thoughts (isn't that why this place is called a "discussion" forum(s)?)

You are correct, to each his own and "taste" is purely subjective, I recognize that

BUT, I place a premium on preserving what is valuable and important as a record of where we came from, warts and all

I feel the same unhappy feelings every time I see a '36 Ford that's been butchered or an old Merc' that's been chopped and dropped, no mater how capable the butcher or impressive the disfigurement. Get that same melancholy feeling every time I visit the South and see that some city council or dumb ass owner has put vinyl siding on a classic Colonial Revival clapboard home that's survived just beautifully for a 100 years as well, to "save money"..........that sort of thing

Soon, all the original examples of the icons will be "gone" (we're almost there now) and those that remain will be out of reach for most who wish to own an example for what it is, and more importantly, for what it was (and appreciate it for how it changed the landscape); no need to assist the realities of time and attrition

Not to sound corny, but for me it's the same as love for a person; if you only "love" them for what you perceive that they can be changed into, then that ain't love. If you feel that way, then let someone have it (or them) that truly does, and go out and find (or build) a "box" (or person) that's more to your liking

Just a lot of effort (and I am sure, significant financial costs) to make something into something it's not when there are many that want it just the way it is. The same amount (maybe even less) of effort could have been spent on simply constructing new MDF cabs, installing the original owner's drivers (he'd still have his spiritual and memory lane connection) and passing the now mutilated ones on to a sincere collector/RESTORER/preservationist

Standard disclaimer: just MY opinion, but I do not think I a alone

[Wagner]

I think that it's a bit pity to make them look like old, plain AR boxes :(
But if the customer wanted them like that...
And add even more aural challenges..................as for your comment, I (obviously) concur

It's definitely a long lived trend, same as painting fine old furniture back in the early decades of the 20th century, or slopping on the faux "antique" finishes during the '70s or the "distressing" so popular during the '80s

Since the '90s it's been all about the "bubinga" and the "zebrawood" redos, so much so that both of those veneers are no longer all that unusual or unique, on anything

Since the asian and 3rd world markets really opened up you find those species all over the place, to the point of overkill

[macaroonie]

All that acidity...

Seems like they'd look right at home in an upscale retro office being driven by a restored SA-6xx integrated amp.
Hope the customer enjoys them for a long time.

Thread Hi Jack , sorry. Back in the day I sold dozens and dozens of those SA xxx Pioneers. I don't recall them ever coming back for repair particularly in light of how many went out the door.

I wonder where they all ended up :dont-know:

[Wagner]

Thread Hi Jack , sorry. Back in the day I sold dozens and dozens of those SA xxx Pioneers. I don't recall them ever coming back for repair particularly in light of how many went out the door.

I wonder where they all ended up :dont-know:

As do I; as recently as the early to mid 2000s they were plentiful and cheap on "craigslist" here where I currently live, then they all sort of disappeared (the low to medium powered ones) Same goes for the Marantz "22xx"series receivers; they were EVERYWHERE until about 5 years ago (and cheap)

I know of the whereabouts of at least one I saved, with a few wirewound resistors from Radio Shack, for a friend who viewed it as "junk"...................until he heard it after the repair

A former girlfriend had abandoned it in non-working condition and with some bent switch levers at his home during the coke fueled '80s; he asked me if I "had any use for it" or off to the landfill it would go (late '80s, early '90s remember?)

After I saw the look on his face, post patch job repair, I let him "have it back"

That was in 1992; he still uses the little amp to this day, a "daily driver"

[grumpy]

I get it. I even agree to a point, were they mine. I don't get the tone. In an open environment, that's my problem I guess. Carry on.

sa-6xx ?... I guess pioneer works in that visual sense also (even though I was thinking JBL :) )

[Wagner]

I get it. I even agree to a point, were they mine. I don't get the tone. In an open environment, that's my problem I guess. Carry on.

sa-6xx ?... I guess pioneer works in that visual sense also (even though I was thinking JBL :) )
Thank you for saying that, sincerely
It is not a problem

Funny, the "tone" thing, what with the 3-ring circus going on as of late in the "news"!
I LOVE it!

All of my life I have encountered many folks, lots of them (but not all), who initially perceived my "delivery", then the popular term was "attitude" (today, I guess we call it "tone") as somehow that of being deliberately critical, antagonistic, abrasive or negative in some way............the descriptives are endless; many have have simply stated "when I FIRST met you, I thought you were a real prick" (or a "dick head", can't remember for sure)
And actually, that one was from the guy with the Pioneer I salvaged (a work mate) who later became one of my best friends

As I am certain that you can imagine, that has worsened in today's ever more "correct" times (so maybe that's MY problem)

Oh yeah, and my favorite nowadays; "why are you (or where is, or "why so...") all that anger coming from?" (or some variation on the the theme) Guess now, if you speak your mind, you must be "angry"?! :nutz: Too funny!

I have just always believed that one is best served in the long run (Life) (and was taught as well) to simply speak clearly and honestly; my years in the trades with machinery helped reinforce that character trait (or what some would consider a flaw) possibly; but in my world, either the work, the fit or the finish was "right" and to spec or it was "wrong"

I am rambling now and I apologize for the big time hijack, but suffice it to say that I am of the disposition that when the woman asks me if the dress makes her ass look fat, and it does, then that's what she needs to be prepared to hear. I cannot, and will not live my life worrying over the feelings of those who just happen to like fat asses that my OPINION or HONEST PERCEPTION may prove offensive if it happens to differ from their own...............and I'm not going to suffocate myself in an open discussion and lie about what I really like or think if I happen to (honestly) dislike it or disagree with it.............it is not the same as a "personal attack" (knocking on folks about things over which they have no control over)

It certainly works both ways, like I said, to each his own and that is FINE. If anyone disagrees with my take on things or just flat out finds me offensive or thinks I suck, then that is perfectly fine with me (too). That is how Life works (or use to anyway) and is The United States of America still (for the time being anyway)

Just not going to jump on any "ooh and aah" bandwagons, about anything when I personally think it (something) sucks, just because it's the popular or "nice" thing to do

I "like" you grumpy (as well as one can on an internet forum), you have always been one of the first people here to lend me a hand of help when I have asked for it and I respect your store of knowledge and for that I thank you; I have always enjoyed your posts here as well (I invariably will learn something).....................I'm just not a "hip" with it modern "sensitive" sort of guy

When talking about inanimate objects it's NEVER personal with me (except that I think some folk's tastes and decisions suck) and I am not shy, nor would I expect anyone else to be, about saying so and why; if anyone doesn't care for my tastes or approach and feels compelled to comment on that fact, then by all means, feel free (just please support your critique and share your reasons), that is how minds are truly changed (sometimes) and how ideas are honestly shared and in more than one instance, in my case, I have actually learned a new way to approach or solve a problem...............and now we've come full circle! :)

[Wagner]

I've finished up this project now.

The bubinga veneer with cane grill cloth is a stunning combination.

I made a couple of small improvements to the crossover design and these speakers are sounding better than they ever have.

Right now I'm enjoying these in my living room, but I'll be packing them up and sending them back to my customer soon.

I've detailed this restoration in four webpages on my website, including detailed cost. Page 1 is http://www.klipschupgrades.com/centuryrestoration.shtml

Greg
Need to fix page 4 there good buddy; that or photo shop your picture of the crossover cap for the LE25 (thought it was just a typo initially, but then it continues through your ad copy) "One thing to note" however is it MIGHT just explain some of your test "results" http://www.audioheritage.org/vbulletin/images/smilies/dont-know.gif
http://www.klipschupgrades.com/centuryrestoration4.shtml

Here's the gist of it:
"The original crossovers are not really crossovers at all. They consist of two capacitors, one for the mid and one for the tweeter, and two potentiometers to control the output of the mid and the tweeter. The midrange capacitor is a 8uFd and the tweeter a 13uFd, which at first glance is the opposite of what you would expect. Normally the mid would have a larger value hi-pass cap. The mid has no low-pass on the upper end (bandpass), and the woofer has no filter on it at all. Not a conventional crossover to say the least."

And by the way, it is an extremely conventional filter design; it's called a passive "first order" Probably the oldest of them all except for just putting a single transducer in a box and attaching an amplifier to it, letting the chips fall where they may and then calling it a day

I borrowed this from Wikipedia to keep things simple; might assist you in understanding some of your frustrating, bewildering and seemingly contradictory results and observations from your 20 hours over four days of hard work collecting that "huge amount of data" on the L100 (A) "crossover" (awfully nice of you to throw that effort in "gratis":

First order[edit (https://en.wikipedia.org/w/index.php?title=Audio_crossover&action=edit&section=10)]

First-order filters have a 20 dB/decade (https://en.wikipedia.org/wiki/Decade_(log_scale)) (or 6 dB/octave (https://en.wikipedia.org/wiki/Octave)) slope. All first-order filters have a Butterworth filter characteristic. First-order filters are considered by many audiophiles (https://en.wikipedia.org/wiki/Audiophile) to be ideal for crossovers. This is because this filter type is 'transient perfect', meaning it passes both amplitude and phase unchanged across the range of interest. It also uses the fewest parts and has the lowest insertion loss (if passive). A first-order crossover allows more signals of unwanted frequencies to get through in the LPF and HPF sections than do higher order configurations. While woofers can easily take this (aside from generating distortion at frequencies above those they can properly handle), smaller high frequency drivers (especially tweeters) are more likely to be damaged since they are not capable of handling large power inputs at frequencies below their rated crossover point.
In practice, speaker systems with true first order acoustic slopes are difficult to design because they require large overlapping driver bandwidth, and the shallow slopes mean that non-coincident drivers interfere over a wide frequency range and cause large response shifts off-axis.