Clone JBL 4344

[ken8168]

Hi all,

I collected the below items and would like to build a clone 4344

2402
2470 with 2307 and 2308
2123H
2235H

Which crossover should I use? some of my componets are different from 4344. Don't know if I can use the same crossover as 4344 or 4343.

thanks.

[speakerdave]

Neither one.

Strictly speaking, and sticking to the actual meaning of the word, a clone is exactly the same.

The advantage of cloning an existing speaker--that is, using the same drivers and cabinet dimensions--is that the needed crossover art is known and can be copied, and it is quite likely you would think it sounds OK.

Using your set of drivers will, staying with the biological analogy, result in a hybrid. You may be able to podge together a network drawing from various sources, but you will not know, nor will anyone else, what it sounds like until you've spent all the money, and you may not like it.

If I had those drivers and for some reason didn't feel like changing any of them and also felt a little reckless about spending money on crossover parts, I would try this: Biamp between the 2235 and the 2123; try the redrawn 3155 for the 2123 to 2470 handoff, let the 2470 die its natural death at the high end, and clone the 3106 for the 2402 high pass.

Others may have better suggestions.

[Ian Mackenzie]

Hi all,

I collected the below items and would like to build a clone 4344

2402
2470 with 2307 and 2308
2123H
2235H

Which crossover should I use? some of my componets are different from 4344. Don't know if I can use the same crossover as 4344 or 4343.

thanks.

I will try and explain.

It’s not unusual to have some variation in drivers when you start out and l note your earlier thread you had similar questions on the LE14.

Firstly l want to confirm you have the 2402 Ring Radiator?
Some people in Japan are using that driver.

If you are using the 2402 you can start that and then eventually you might acquire a 2405 used in the 4344- 4344mk11.

The 2123H is a variation on the 2122H used in the factory 4344 and larger 4345. The 2123H is more efficient and has different response characteristics. The 2122H is now obsolete and diy people are using the 2123H.

The other question is what diagram does your 2470 compression driver have in it?
You need to look at that because these Jbl monitors used the titanium D16R2425 diaphragm.

The tricky question or barrier is what crossover schematic to follow? The key to these networks is how they blend the 4 drivers so it actually sound good.

The crossover schematics used in the above systems are specifically designed for those particular drivers in those respective models.

The below two links show the schematic used in the 4344mk2 and the de facto equivalent 3144-3145 network used in the 4344-4345. The main difference is the MF network filters for the 2123H versus 2122H.

http://www.audioheritage.org/vbulletin/showthread.php?24283-4344-Mk-II-network

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

You might consider the 4344mk2 schematic. But for this to work best you need an 8 ohm impedance diaphragm D8R2425. This network is optimised for the acquplas dusted titanium diaphragm D8R2425 in terms of tonal balance and driver integration. It’s very nice when you get everything right but availability of the acquplas substance is difficult.

So the solution is to take the MF filter section in the first link and use this in place of the MF filter section in the second link. Use the D16R2425 diagram.

Now the 2402 has different characteristics to the 2405 and that is something you will have to evaluate. You may also need to experiment with the UHF filter to get the best blend with the compression driver. In Japan some people use the Ring Radiator (or a 3rd part brand bullet knock off).

Finally this is diy and starting off you won’t always have all the exact drivers. But for the purposes of naming conventions and to avoid confusion your project is a diy 4 way monitor based on the Jbl 4344 but it’s NOT a clone.

Lastly if you have available a 2nd stereo power amp please consider Biamping with a stereo active crossover. This is a more effective approach to powering this type of jb monitor.

The cost of the full passive crossover network for the woofer filter is largely offset by the cost of an entry level active crossover.

I hope this brings some clarity.

You may have other questions and if you wish you can pm message me if you wish.

Ian

[ken8168]

Thanks you for both of your comments and advises. I rephrased my project as DIY JBL 4 ways speakers is more appropriate. thx.

It seems the crossover setup is not an easy task but I think I have no way to go back now, haha...Hope Experts in here can give me advices and hints.

Yes, previously I planned to use LE14 but finally I acquired 2235H and 2123H (Both are still on the way sending to me)

For 2402, I have no Ring Radiator for 2402. My 2402 is 8 ohm.


For 2470, I have installed replacement 2420 16 ohm diaphragm. I will use this diaphragm first.

https://reconingspeakers.com/product/jbl-2420-2421-2425-2426-2427-2470-aftermarket-diaphragm-16-ohms-spiral-edge/

and I also have original brand new 2460 16ohm phenolic (But I measure the DC ohm is around 6.x ohm only, is this normal?). I will install these phenolic later when I have completed the crossover to see the difference.


For 2123H and 2235H, they are with original cone.



I found the crossover of 3143 (JBL 4343) and 3144 (JBL 4344) as follows:


Speaker
crossover
Speaker
crossover


2231
300Hz
2235
290Hz


2121
1.25kHz
2121H
1.3kHz


2420+2307
9.5kHz
2425+2307
10kHz


2405

2405H













Should I refer to High freq part of 3143 and Low freq part of 3144?
However, no idea about mid range and ultra high...

As per Ian's said, I should start the crossover by referring 4343 MK2?

Besides, I have two power amps which can do bi amp for 2235H and 2123H + 2470+2402 respectively.

Thanks.