Building a 4343 Clone

[santashooter]

Hi there
I am starting out to build a pair of 4343 speakers.
My thoughts are, that wether or not to build the 4343B or the 4343A, depends on what kind of 10" I source(2121A or 2121H - I would prefer Ferrit magnets as I do not have remag capabilities on hand).

I am of course aiming towards sourcing the following:
2405
2121
2231

2420 + horn + lens (I have these already)

And then build the 3143 network (Or the Charged coupled network, before I can source the original).

I would very much like the speakers to look and sound as the 4343 speaker, as they were built "back then" - not doing something different that makes them something else.

Just to be clear, (Because I have possibility to buy both 2122H and 2235H speakers) How different are these, in terms of the final product?
Would you, knowledgeable people here, consider that to be wrong, or are they compatible replacements for the 2121 and 2231 drivers.

It could be a point of "getting going" in the project, to buy 2122h and 2235H for now, build the speaker and then keep watch for 2121 and 2231 drivers along the way. But not if they are sonically "wrong".

[Ian Mackenzie]

Hi there
I am starting out to build a pair of 4343 speakers.
My thoughts are, that wether or not to build the 4343B or the 4343A, depends on what kind of 10" I source(2121A or 2121H - I would prefer Ferrit magnets as I do not have remag capabilities on hand).

Just to be clear, (Because I have possibility to buy both 2122H and 2235H speakers) How different are these, in terms of the final product?
Would you, knowledgeable people here, consider that to be wrong, or are they compatible replacements for the 2121 and 2231 drivers.

It could be a point of "getting going" in the project, to buy 2122h and 2235H for now, build the speaker and then keep watch for 2121 and 2231 drivers along the way. But not if they are sonically "wrong".

Okay

I will go first

The short answer is if you can obtain a 2122H use it as in a 4344 at a later date or put it on ice.

I Will gladly buy it off you later. These are now impossible to obtain

The 2122 is a smoother driver than the 2121 with somewhat different frequency response

It has a somewhat different passive crossover as a result

The devil is in the detail

It’s a good upgrade path if you have a clapped out old 4343.

The 2235 is the full SF conversion from alnico. The Vc has a higher power rating and the spider if l am not wrong is progressive. But it’s tuning and everything else make it interchangeable with a 2231a

My suggestion is acquire the 2122H now along with the 2235H to get you going.

Build the baffle as a 4343 and use a new equivalent 3145 passive crossover for now.

Buy a DR162425 diaphragm and put in the 2420 or buy a 2425 compression driver as the 3145 crossover is optimised for this driver.

When you later acquire a 2121 then use it with a clone 3143 network for the purposes of authenticity

You could then decide what to do with the 2122. I would build a 4345 authentically

This is my rational.

[santashooter]

Thanks Ian - that goes well along the lines of my thoughts!

I don't think I will change the diaphragms in my 2420's though as these are with red wax seals, and sounds amazing as is.
Would putting foam surround on a pair of LE10A be a better option, in terms of matching the 2121 frequency response, so I can use the 3143 crossover and keep the 2420 diapragms?

[Ian Mackenzie]

No leave the existing surround


The LE 10a and the 2121 are 10 inch drivers
That is where the similarities end

The reference efficiency of the LE10a is 0.6%
The reference efficiency of the 2121 is 2.7%

That won’t stop you trying the LE10a

The crossover won’t be optimised but you can try it.

The sensitivity of the 2420 and the 2405 will be way higher so the Lpads will need turning back -10 dB or more.

The LE10a will go lower

You can build a 2121 using after market recone kits and finding a suitable 10 inch basket

See the 4343 reference thread

I would not trash the LE10a. In fact l would look at building a 4313

[santashooter]

You can build a 2121 using after market recone kits and finding a suitable 10 inch basket


I would normally look away from ever using an aftermarket kit, but this sounds interesting - I can't find the post/thread though?

[Odd]

Using Google, the search feature in the forum is not very good.

http://www.audioheritage.org/vbulletin/showthread.php?16951-4343-References-Thread

[santashooter]

Using Google, the search feature in the forum is not very good.

http://www.audioheritage.org/vbulletin/showthread.php?16951-4343-References-Thread
Oh I found the thread, but not the post about using an aftermarket 2121 kit, with good results:blink:

[Ian Mackenzie]

http://www.audioheritage.org/vbulletin/showthread.php?16962-Field-Guide-to-the-JBL-10-inch-Midbass-driver-2121-2122-2123&p=391415&viewfull=1#post391415

An E110 basket might work but needs to be confirmed

You need to contend with the authenticity on two fronts, component authenticity and performance authenticity.

In attempting to build a 2121H for example from another basket you will have conflicting aims as on the one hand you might get the performance but you won't have driver authenticity as its not a 2121 basket. You midge be able to get a foil cal custom made for the 2121

Thinking about it logically I would not destroy the LE10a without knowledge of other real options.

Also I have not used the after market 2121 recone kit but people are using that option where a reform is not an option.
There are some Lansalloy surround versions that look really cool on ebay sometimes

I have heard that sometimes JBL do run of recone kits like the 2121 so I would not entirely rule it out.
But you can't buy a recone kit from JBL as it has to be installed by a JBL authorised service agent to meet JBL warranty.


I would PM member Edgewound to get clarity on what other baskets can be used to make a 2121?

So you in a bit of a jam unfortunately

I suggest you contact Ken (Edgewound)

[santashooter]

Thank you Ian
I have a contact that are able to order parts from JBL, so If they are on stock at JBL I can usually get my hands on them.
But 2121 is out of stock.
I am looking towards making a 2122H from a 2123 basket (I have a couple of these, with damages cones but in otherwise good condition).
I think I'll stick with the 2122H until I find a 2121.
But I'll try to keep the crossover, as if I have a 2121 installed. You mention that they do have a different frequency response, then the question is just how big that difference is :skeptical:

I am as of now trying to get the 10" and 15" secured, as soon as I have those I'll start on the enclosures.
I wish there were detailed plans on these, but I haven't been able to find good plans, so it is reverse engineering based on pictures, drawings and the plans for other speakers on here.
for example, I have the very extensive drawings from Odd for the 4344 cabinets, and measurements like panel-thickness, trimpanel and so forth should be identical between these.

best regards
Soren Iversen

[Ian Mackenzie]

The baffle plans are the problem
Mhttp://www.audioheritage.org/vbulletin/showthread.php?33374-Baffle-Cabinet-Plans-of-the-4343

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=57398&d=1351925330

[Ian Mackenzie]

Concerning the 2122H you will need to use the new equivalent 3145 crossover.

Should you wish to selll it after you decided to revert back to the 3143 it will be snapped up in a nanosecond second

Link to new equivalent 3145 crossover

The 3144 and the 3145 crossover are identical

http://www.audioheritage.org/vbulletin/showthread.php?39310-Giskard-Charge-coupled-3145-crossover-network-iron-core-inductor-source&p=401524&viewfull=1#post401524

For those watching if you are considering jumping from the 4343-4344 on the fly l will be able to answer your desire soon.

[santashooter]

The baffle plans are the problem
Mhttp://www.audioheritage.org/vbulletin/showthread.php?33374-Baffle-Cabinet-Plans-of-the-4343

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=57398&d=1351925330
Thank you very much, for the link to the baffle plans!
I assume the thickness of the plywood is kept the same across different 43XX speakers?
I am going to peek inside a pair of 4333X soon, (Mining-style, with headlamp and everything :D) and will be able to measure baffle thickness, trim overhang and side thickness from that pair.

I'll go with the 3145 network with Giskard's list.
That'll provide a good platform.

I will however try to find some of these parts locally, as it might be very expensive to ship everything from, rather than finding the stuff in Denmark/Europe - but let's see. From the diagram it seems the 5.4mH is an iron core coil, but the parts list Solen component references an air coil (the L125.6)?

[Ian Mackenzie]

As l recall Jbl used a 15 ply baffle.

Once you get your Jasper router jig set up let us know and post some pics.

My suggestion is do some practice cuts and don’t rush.

I personally found the baffle the most tricky aspect of the construction.

The enclosure walls were particle board back then

I would use mdf or veneered mdf.

Be sure to test your Jbl blue pain before application...Lol

[santashooter]

As l recall Jbl used a 15 ply baffle.

Once you get your Jasper router jig set up let us know and post some pics.

My suggestion is do some practice cuts and don’t rush.

I personally found the baffle the most tricky aspect of the construction.

The enclosure walls were particle board back then

I would use mdf or veneered mdf.

Be sure to test your Jbl blue pain before application...Lol
I think I'll go with particle board for the sides at least.
Always go slow - measure twice, cut once;)

For the paint, the 4344 clone build on this site here http://www.audioheritage.org/vbulletin/showthread.php?34471-DIY-JBL-4344-project/page6
I'll make a lot of tests and sample them to the 4333 I have a chance of visiting.

[macaroonie]

Lets not do the MDF thing , OP is in Denmark , Baltic Birch ply is commonplace and the dust won't kill you.
From memory baffle is 25mm and the sides and back are 18mm with substantial. bracing.

Just as a second thought , why not DSP the whole shebang. M4 !!

[Ian Mackenzie]

Lets not do the MDF thing , OP is in Denmark , Baltic Birch ply is commonplace and the dust won't kill you.
From memory baffle is 25mm and the sides and back are 18mm with substantial. bracing.

Just as a second thought , why not DSP the whole shebang. M4 !!

In the other thread Authenticate a 4343 the poster wants authenticity period.

[santashooter]

I am trying to hit authenticity where possible - I know there are easier, and even better materials to choose from, but in the end, I want my clone to be a JBL 4343 reproduction, not something that looks like it.
The first hurdle is going from imperial to metric measurements in available sheet thinknesses.

From what I have been able to gather from seeing pictures of 4343 baffles, it seems the baffle is also made of particle board, at least the square upper part, together with the mid-box.
The back is also Particle board.
The bracing seems to be pine or Birch bracing, based on the pictures alone.
I'll need to verify baffle, back and side thicknesses before I can order sheets.

[santashooter]

i have been looking at the parts list from Solen - Wowza, that is a hefty price tag!
and then more than 300 in shipping alone + import taxes.
Been looking at local Jantzen components instead, but some values are impossible to find (take for example 160uF caps) - is it crucial for the crossover, that we are hitting exact values here?
What is the rule for combining caps and resistors to match the values in the diagram?
and do anyone have good input on somewhere in Europe, from where I can order this stuff?

[Ian Mackenzie]

Okay

I will try and frame this area with some economic rationalism.

Imagine you were in production like Jbl.

What they did was evaluate alternatives.

The parts in that list are the ideal choices and because it’s charge coupled you need four times as many capacitors so it’s not an inexpensive aspect of the project

Secondly, you can Biamp which avoids building the woofer filter and some parts of the 2122 filter

Biamping is where a high level active filter splits the frequency range into two halves after the preamp so you have low and high outputs that go into a a power amp then the woofer (low) and the mid+horn+slot (high)

In general terms it’s the preferred way to run this kind of loudspeaker
You will need an active crossover and two Stereo power amps.

Looking at the parts some areas there options in terms of capacitors.
For example in the very early systems Jbl used Mylar capacitors (green caps these days).

What Jbl did in the last iteration of this system the 4344mk11 was to select some cost effective alternatives to expensive polypropylene capacitors in key areas which made a lot of sense. The woofer filter capacitors are non polarised electrolytes types (NPE) bypassed with small value polypropylene capacitors like 0.01. The woofer filter was not charge coupled in production.

So you can save a heap of money there.

Next the 2122 high pass mid filter capacitors Jbl selected non polarised electrolyte (NPE) bypassed with small value polypropylene capacitors like 0.01. These capacitors are charge coupled.

The low pass section of the 2122 filter and the high and uhf filters use polypropylene charge coupled capacitors. Basically all the capacitors in red on that list could be non polarised electrolyte (NPE). The rational is cost. You will probably not use this aspect of the crossover once you Biamp and after that you probably won’t go back to full passive operation.

Don’t worry about working out a list right now. I am just relaying you an approach

It will do exactly what the other list does but in a far more cost effective manner.
I can draw it up for you if you like.

In the diy space of course people don’t have cost limitations only the depth of their pockets.
To get you up and going the above is being smart. Later on once you sort out the drivers you can go for broke if that’s your plan.

Send me a PM and l will go through it in more detail.

In the diy space crossovers and in particular capacitors attracts a lot of conversations so beware

Finally, check out Parts Express. Their shipping cost might be lower

Edited for clarity 5.14 pm ESAT

[santashooter]

Thank you Ian

I would like to go full passive first time around, but you idea about making a more budget filter, that is still in line with JBL thought, sounds really nice!
I would like to take you up on your offer for a revised filter!

One of the things iv'e noticed, is that some of the crossover values needed for the original filter, are not available here in DK.
As if there are some standard values, and some values are not? or am I just stuck on the wrong side of the ocean? :blink:

an example is the 160uF capacitor - the available models are 120uF, 150uF, and 220uF - I guess I could just parallel a 150uF and a 10uF?

[Ian Mackenzie]

Let me get back to you in a couple of days with the solution

[Dr.db]

One of the things iv'e noticed, is that some of the crossover values needed for the original filter, are not available here in DK.
As if there are some standard values, and some values are not? or am I just stuck on the wrong side of the ocean? :blink:


No, there are plenty capable companies in europe.
You allready named Jantzen in Denmark, I believe Duelund is somewhere in scandinavia too but in my opionion a little bit on the voodoo side. So beware as Ian said, no need to pay 500€ for a single capacitor.
But I have experienced Mundorf (in germany) to be very helpful. You can order your individual values there. Even for a single part!

What exact values for the inductors are you looking for?



an example is the 160uF capacitor - the available models are 120uF, 150uF, and 220uF - I guess I could just parallel a 150uF and a 10uF?

Yes. Parrallel 150uf with 10uf results in 160uf total value. Put them in series and it will be the opposite way...

[ivica]

Okay

I will try and frame this area with some economic rationalism.

Imagine you were in production like Jbl.

.......
Secondly, you can Biamp which avoids building the woofer filter and some parts of the 2122 filter

Biamping is where a high level active filter splits the frequency range into two halves after the preamp so you have low and high outputs that go into a a power amp then the woofer (low) and the mid+horn+slot (high)

In general terms it’s the preferred way to run this kind of loudspeaker
You will need an active crossover and two Stereo power amps.

......ESAT

Hi Ian,

I think more important applying bi-amp-ing (with active LF, HI filter round 300~500Hz) is that it would be avoided interaction of the large coil inductance with the speaker characteristic so mid-bass emphasis would be avoided . Such things has been more elaborated by the G.Timbers when he has been talking about JBL4345 network and possible improvements of such great speakers (even there he has not mentioned, may be 2420&2307 has to be exchanged with 2441&2311, as MY PERSONAL opinion too).

regards
ivica

[Ian Mackenzie]

I am well aware of that

Please re read my earlier post(s)

People are at times polarised or obsessed on a single quest like having the best.

That’s fine if that is the focus but it’s not here.

From the outset users focus has been about authenticity of the original design

The users desire is to use full passive at least for now so l am offering assistance within that scope

[santashooter]

Hi all
The reason I want to use full passive (would be nice with the possibility to add a biamp-switch, at some point) is that I also collect vintage amplifiers - for example I use the Marantz model 16 as my main driver right now - I have a couple of other amps from Marants and Luxman as well, and a Marantz model 250 is going to drive the 4343 when they are done - but I don't really want to be dependent on having 2 amps in function all the time, as they are constantly rotating in and out of service, maintenance and storage;)

[Ian Mackenzie]

That makes perfect sense

[santashooter]

Okay - a tiny update:
I bought two original 3145 crossovers, per Ian's recommendation, And I've ordered some speakers and are sourcing the last parts.

Status today:

Bought:
Pair of 3145 Crossovers
Pair of JBL LE85 + H91 + Lenses
Pair of 2231A with 2235 cones
Pair of L136A with 2231 cones.
Pair of C8R2122H recone kits

Tomorrow I am visiting a guy who has listed the following for sale:
pair of 2123 baskets only
Pair of 2405A (without diapraghms, but he might have an original pair lying around)

All in all, I think I have a good basis for the project - once all the drivers are either ordered or in-house, I'll start working on the enclosure... I hope tonight, that I can start building a CAD drawing from the measurements I have.
:D

[Ian Mackenzie]

There’s no stopping you now

[santashooter]

I have an enclosure question:
Basen on the JBL pro 4343 publications (http://www.jblpro.com/pub/obsolete/4343b.pdf) it says the following in terms of enclosure materials:
"To eliminate resonance, the enclosure isconstructed of dense 19 mm (0.75 in) and 25 mm (1 in)stock with a 15-ply baffle panel"




first off - what dimensions are used where? - 19mm particleboard on the sides and 25mm on the back-panel or opposite?
Furthermore, the plywood baffle text, is a bit of a surprise as pictures in this thread: (for example) http://www.audioheritage.org/vbulletin/showthread.php?37379-JBL-4343-restoration-progress-and-quite-possibly-a-lot-of-question-along-the-way
Clearly shows the use of particle board on the baffle, both for the upper section and the LF baffle portion...
Can anyone shed some light here?

[Ian Mackenzie]

Another thread here

http://www.audioheritage.org/vbulletin/showthread.php?38726-My-JBL-4343-repair-story

The one inch is the outer walls

3/4 is the dog box

On the baffle we have all read the flyer

I suggest the flyer copy from marketing preceded the actual production run.

The prototype from their custom shop might have been plywood baffle.

I would personally use ply for the upper baffle if you intend to remove and rotate it like the original at particle board or mdf is easily chipped

[santashooter]

Thanks for the clarification Ian!
that makes sense! - i don’t think i’ll ever flip the upper baffle board, but i’ll consider using plywood here :)

[Ian Mackenzie]

I thought the Japanese members thread had authenticity

[santashooter]

I absolutely agree - I've been at that thread before - great work, and great pictures!

Again, thanks for the clarification, not easy when documents doesn't correspond to reality!
To muddy the waters even more, my doubt was cause because I know JBL have had the local import agencies in some countries make their own enclosures by JBL America specification. That was the case for example in Denmark for the Lancer series speakers - almost all enclosures were built locally in Denmark, because import prices were cheaper and easier on drivers alone.
That, and all the great cloning work being done in these threads made me uncertain what was "real" ;)

[Ian Mackenzie]

If you read closely on the previous mentioned thread the restorer was the 3rd owner as far as we know

The original purchaser is anyone’s guess

Once the original owner passes on the stock box over say EBay the odd of an authentic system plummet like a rock.

Things get taken out, modifications get made, restorations may not adhere to the original.

I have pics of a crossover that was butchered then returned attempted to stock and on sold as stock.

What you don’t see you don’t know until you really open up everything or a problem arises.

In another case a member bought all the drivers for a 4344 project off eBay.

It was his dream.

Every driver had a problem! I had to mitigate 4 times back to each driver after l built the crossovers because it apparently did not sound right and did not test right on location ( the other side of the world)

Don’t assume anything is good until you know it’s good.

Particularly off EBay.

Not wanting to scare you but get your drivers checked out by a qualified service agent before anything else.

Unfortunately this is the nature of loudspeakers recycling through EBay where what a seller doesn’t know he doesn’t know. People make adhoc changes then try and make it like it was and move on.

So you have to validate and break that cycle.

I’m not reading the riot act here.

Just be cautious and validate as you are doing.

[santashooter]

Today is the last day before easter-holiday and I was lucky that all my incoming packages arrived hours before I was to leave for my parents house.
80640
80641
80642

So 2X 2122H recone kits directly from JBL, 2X 3145 Crossovers and 4x 15" woofers, 2x 2231A with 2235 recone kits, and a pair of 136A's as well.:D

[berga12]

Lucky man!!! how you can find stock crossover!?!

[santashooter]

It was on Ebay, in the Netherlands. Ian pointed me towards them, and then it was just clicking buy now ;)

[Dr.db]

Bought:
Pair of C8R2122H recone kits



Where did you buy these?

[santashooter]

I know a guy ;)
these are from the Internal Harman Kardon Netherlands System - so a European service partner should be able to get them ;)

[Dr.db]

Thanks a lot :)

[Ian Mackenzie]

It was on Ebay, in the Netherlands. Ian pointed me towards them, and then it was just clicking buy now ;)

I Googled JBL 3145 to find the old JBL schematic and the EBay listing came up.

I could not believe it!

It was like it was meant to be.

[santashooter]

I am a very happy guy - CAD drawings for the enclosures are in the works now. Along with allocating time for the build process. I can’t help but think I am underestimating the scope in ny head.

[santashooter]

A quick question regarding ordering L-Pads.
Can someone please verify for me the types I need:
the UHF should be 50W and the 2 others 100W models - the 50W should be 8 ohms and the 100W 16 ohms?
I am using the stock 3145 crossover, and running the 2122H as the lower mid driver.

[Odd]

16 ohm with long shaft is difficult.
I bought these;
ebay (https://www.ebay.com/itm/Speaker-L-Pad-Volume-Attenuator-AT-50H-50W-RMS-16-Ohms-potentiometer/123019052370?hash=item1ca481c552:g:79cAAOSwY3RXJNr V)
They are of good quality.
50W or 100W does not matter for home use.

[Ian Mackenzie]

50 Watt 8 ohms

Also check the shaft length

I don’t think 100 Watt will fit due to spacing
Check Parts Express

[santashooter]

Okay so wattage is not important, but the impedance is right?
8 ohms for the UHF and 16 Ohms for horn and 10”?

[Ian Mackenzie]

The way the network operates you need 3 x 8 ohm Lpads per box

If you look at the distance between the Lpad on the foilcal the 100 way would not fit

[santashooter]

Hi there
the project is going along slowly, still need to buy plywood, and i am looking for a local supplier for the walnut trim.
while waiting; does anyone know where I can source new labels for drivers? My 2405, came without the label on the back, so I would like reproductions from somewhere.

[Odd]

Try and contact Paolo Gibertoni
He has previously made fine copies.

Paolo Gibertoni <[email protected]>

[Ian Mackenzie]

Just google Jbl foilcal

I got these but there are others

http://italianxshop.blogspot.com.au/2016/03/jbl-4430-4435-foilcal.html?m=0

https://m.ebay.com/sch/i.html?isRefine=true&sid=sign--shop&isRefine=true&_pgn=1&_mwBanner=1

[richluvsound]

This guy does beautiful work . I’ve used Paolo also . Great to work with ? But Edly’s work is outsatanding .

[DES-1]

For those building clone or 'tribute' speakers... do you place any form of identification on them to distinguish from factory? My project speakers deviate enough from the original design so unlikely they'll be confused even if I choose to label them 4345 with repro badges. I might look into a custom set of badges (or make myself in Photoshop) to complete the factory look but add something so as not to upset the JBL gods :eek:

[Ian Mackenzie]

Good point

I don’t think so but the are some things that make it obvious if you know what to look for.

Such as the authentic ma- 15 clamps, the original grill fabric and the way the emblem plate is attached is not common among clones
The real giveaway is the authentic 3145 stock crossover assembly. That can be seen from the rear as well as inside
I recall the authentic factory 4345 has stamped serial numbers in the foil cal but that could be done on a reproduction

[santashooter]

Thanks for the links - I have found the foilcals in some beautiful reproductions, it was more driver labels for the backside of the drivers.

It is a conundrum - I am are building a clone of the enclosure - the drivers are all JBL and the crossover the same.
My enclosure is as close to original spec as I can possibly get. I will be putting an aftermarket foilcal on them, but they will not have a serial number, and that is where the deviation comes in - It will therefore never claim to be a production 4343, but still a JBL 4343.

[DES-1]

You've been incredibly fortunate to gather those components in such condition. Looking forward to seeing the cabinets and completion. These will likely be very valuable and true clones!

[santashooter]

Thank you DES-1 - I hope to get building later this month, and I'll post images here when construction starts.
I am moving slow and steady, doing things right :)

Again, in my mind JBL has been known for providing cabinet plans, selling drivers and crossovers as parts with their own production number, and therefore what constitutes a "real" 4343 and what is a clone is somewhat a sliding scale. (Danish Lancer models had enclosures all built locally in Denmark, not by JBL)

If I build a true clone, where there is no difference in construction, materials or parts (that is not entirely the case with my build, but for the arguments sake, let's play with that hypothetical standpoint)
It WILL be a JBL 4343 - it is exactly the same thing - the difference is only contingent on who built the enclosure, JBL factory or me - in my mind the difference therefore would be not in the model name, but in the serial stamp - JBL factory would print serial tags on their units (IE a documentation of a serial production)- My speakers would be a JBL 4343 but not be a part of JBL factory production and I would either have to stamp them with my own number system, or simply leave them blank.

If I went down the modding or "home-brew" route - I would like a custom foilcal more than a reproductionopy, since the speaker would otherwise not be what it says on the foilcal.

When I am done with the enclosures and assembling my speakers, there will be a difference between a true JBL 4343 and my speakers: the 10" and in the crossover - I use the 3145 and a 2122H instead of 3143 and 2121A - But the enclosures will wait for me to get a hold on the 3143 and the 2121A for me to put in - therefore the "reproduction" foilcal that says JBL 4343 - some day, that will be true. ;)

[Ian Mackenzie]

I have not forgotten about the 3143.

It’s in the works

[santashooter]

No worries Ian - it is not a first priority right now, so take all the time you need!
Finding 2121As is not an easy task, and i have a substantiam build Job ahead of me before that :)

[santashooter]

So, I've built myself a new workshop at my parents house - it is a great little place, with all the necessary tools and the space for leaving the project, when I do something else. It is in Jutland or the big main part of Denmark - I however, live in copenhagen. So it is a bit of a drive, and I usually Get a bit tired of the country-life after a small week, so the project is going to come along slowly.'
This however is probably a good idea, considering my usual "get things done now" attitude, that could tend to do things quickly rather than correctly.

But a little set pictures of the drivers, workshop, veneer and start of gluing things together.

The components (with both my 2231 with 2235H kits and K130 with 2231 recone-kits.)
2123H with new 2122H recone kits
LE85
2405 with new diaphragms.
http://auditur.dk/JBL/1.jpg
Walnut pieces for the wood-trimhttp://auditur.dk/JBL/2.jpg
The 3145 filters
http://auditur.dk/JBL/3.jpg
28 pieces of wood altogether
http://auditur.dk/JBL/4.jpg
http://auditur.dk/JBL/5.jpg

Testing colours: the first tests are way to bright for a 4343 - might be okay for a 4313B or similar later speaker, but I found the correct color to be a combination of 80% NCS S6020 and 20% RAL 5014

http://auditur.dk/JBL/7.jpg


The new workshop: Two tables are a good thing to have
http://auditur.dk/JBL/8.JPG
Lower baffle-board measurements for the woofer and ports.
http://auditur.dk/JBL/9.JPG
All panels are made of 24mm plywood, made up of 2 12mm pieces glued together to make a very rigid 24mm panel - the boards have been cut up, so I have a 12mm overhang places where I either countersink the edges for locking panel (used on the backpanel and lower baffle) and also for giving me more glue-surface for the top and bottom panel.
http://auditur.dk/JBL/10.JPG

Here I am testing the method for counter-sinking the baffle and backpanel - a 12mm wide, 12mm deep slot routered into the joined panels.http://auditur.dk/JBL/11.JPG

[Ian Mackenzie]

Wow, your very organised.

My one tip is take your time.

[santashooter]

Wow, your very organised.

My one tip is take your time.
Thanks Ian!
yeah, measure twice and cut once ;) - a lot can be thought through and worked out in the preparation.
luckily I have loads of time during the summer. A family member needed a place to stay with kids until september, so I gave up my flat - my flat is therefore not particularly big-speaker friendly anyway :)

[santashooter]

So - the summer is here and tiny Denmark has seen some weeks with nothing but sunshine.
Luckily a few days of clouded weather and a cold wind forced me into the basement where I could proceed with the boxes and the 2405, which needed new diapraghms.
81557

81558
And then on with the wood!
81559
81560
81561

[santashooter]

A slimming tip: You WILL look tiny, standing next to a 4343 :D
81562

Test-fitting the drivers - Upper baffle just laid in place - still a snuck fit, so I didn't want it to fall in just yet!

81563
81564

[Ian Mackenzie]

Looking good 👍

[santashooter]

Thanks Ian!
I am very pleased so far!
Next weekendt i'll build box number 2, and then move on to trim, painting and veneer-work.
L-pads, wiring and reflex tubes are in route - so the only thing i am actually missing is the foilcal at this stage.

I might plug everything in and give it a listen before doing trim and veneer-work, as I don't want to be too eager to get done when the delicate work begins.

[DavidF]

Thanks Ian!
I am very pleased so far!
Next weekendt i'll build box number 2, and then move on to trim, painting and veneer-work.
L-pads, wiring and reflex tubes are in route - so the only thing i am actually missing is the foilcal at this stage.

I might plug everything in and give it a listen before doing trim and veneer-work, as I don't want to be too eager to get done when the delicate work begins.

In the way I work with such projects, the more I get down to the finish and detail the longer it seems to take. It always seems there is one more thing to do and one more thing beyond that. I guess that it is the level of precision and care that becomes more time consuming, but there is also the anxiety to get it done. Thanks for sharing the work in progress.

[santashooter]

In the way I work with such projects, the more I get down to the finish and detail the longer it seems to take. It always seems there is one more thing to do and one more thing beyond that. I guess that it is the level of precision and care that becomes more time consuming, but there is also the anxiety to get it done. Thanks for sharing the work in progress.

I absolutely agree David!
It is a balance: you want it done to be able to experience the final product, but still it has to be done right. More times than i can count i've rushed through only to make mistakes, that overshadow the end piece.
That can't happen here. Also this is my 4343 project, a project i've been planning for years - not enjoying the process would be mad ;)

[santashooter]

So!
I couldn't resist and had to get a small pre-listen of the speaker:

http://auditur.dk/wp-content/uploads/2018/07/26.mov

And with that began the work on speaker 2 and the trim:
81678
81679
81680
81681
81682

[Ian Mackenzie]

Thank you for posting the progress update.

You have done a first class job

[santashooter]

I finally had some days In Jutland where I could work on the cabinets, veneering, routing and painting.

So far I am very satisfied!

82004
82005
82006
82007

I have to go back to Copenhagen for a small meeting tomorrow, but hopefully I get the first listening impressions in around Saturday or sunday:applaud:

[ompdiburi]

Nice job, they look beautifull!:bouncy:

[gdmoore28]

Those cabinets are just beautiful, my man! JBL blue is always a standout color, of course, but the veneers are so nice. Kudos on a great job of cabinet building!

Question: are you gluing two sheets of 1/2" MDF together for a total of 1" thick panels? That's what I did in the side portions of my Altec build, pictured in my avatar. The remainder of the cabinet ranges up to 2.5" thick MDF. Extremely heavy at 200+ pounds per cabinet, but cabinet resonances are near zero. I'm a real believer in thick, rigid cabinets!

GeeDeeEmm

[srm51555]

They look awesome, nice work

[santashooter]

And now, Listening Listening and Listening.
so far they sound every bit as good as imagined.
82015

[ivica]

And now, Listening Listening and Listening.
so far they sound every bit as good as imagined.
....

Hi santashooter,

Where are 2308 lenses ???

Ivica

[santashooter]

Hi santashooter,

Where are 2308 lenses ???

Ivica

Good point Ivica - this afternoon i'll mount the Velcro for the lenses and they get on;)

[berga12]

I’m the only one that do not like the listening with lenses?

[santashooter]

I’m the only one that do not like the listening with lenses?
Well i can't say yet - i have only listened without, but i need them mounted anyway and then i'll see what I think;)

[santashooter]

Here comes a few more pictures taken with a better camera:

82016
82017

[Mannermusic]

I’m the only one that do not like the listening with lenses?

The lenses definitely affect the character of sound on those horns, neither good nor bad - a trade-off. I generally prefer the Selenium 14-50 . . . but they aren't "perfect" either. It's all an approximation (as Greg Timbers stated some time ago) in any case. Good hobby!

[DES-1]

Those are stunning! Congrats. Look every bit as good as factory, maybe better because they are new. Your progress reminds me to get back to the next steps on my project.

[berga12]

In any case,amazing wood work!!! Congrats!

[Mannermusic]

In any case,amazing wood work!!! Congrats!

+1!

[ivica]

I’m the only one that do not like the listening with lenses?

Hi berga12,

If not speaking of personal favor, without 2308 Jbl horns such as 2307, 2311 and 2312 would have very narrow horizontal dispersion, and about +3 or +4 dB emphasis FR over about 3.5kHz. Than can be easily proved by measurements. So using standard Jbl networks such as 3143, 44/45 would need some corrections and tuning.

Regards
Ivica

[berga12]

Hi Ivica, I know,I was just speaking about personal taste, even if it’s not intended By JBL developers. :)

[santashooter]

Hi all - I am vey happy with my result but there is a part missing:
from what i've gathered JBL enclosures were both oiled and waxed.
Mine are just oiled right now using the 3 parts linseed oil 1 part Gum turpentine mix, but what wax should i use as a finish?
I live in Denmark, so some brands might be hard to obtain - any suggestions are appreciated.

as you might have seen/quessed i am very strictly adhering to originality, so I would like to get as close as possible to what JBL used themselves.:D

[DogBox]

Mine are just oiled right now using the 3 parts linseed oil 1 part Gum turpentine mix, but ....I live in Denmark, so....any suggestions are appreciated...very strictly adhering to originality, so.... :D

So,... I thought you would have used "Scandanavian Teak Oil"??? :p Sorry, I couldn't resist that!!! :D

Wow! What a wonderful build! I am Soooo envious! I still haven't got boxes for all my drivers - although I AM listening to them...

I hope you're up to plenty of questions so far after your project.. They should have really started to settle in by now and 'really' sound nice!!!

DogBox
[Steve]