JBL 4320/4333/Upgrade/?

[MadsKaizer]

Hello all

For a long time I have been looking to become a JBL 43xx series owner and it happened just recently that I had pair offered and I bought them.

I have a little difficulty pinpointing their model as the drivers are collected for empty cabinets, so it is not original retail speakers.

I have seen both 4320 and 4333 use this type of cabinet and unfortunately there is no SN, just the glue is left on the back side.

It has the 4 pins holding the front frame in the middle of the side, not in the corners.

There is cutouts on the back for additional divider network and for integrating a amplifier.

I did the new front frame clothing myself and the JBL logo is also added by me.

Right
3120A crossover (11041)
2231A low frequency driver (33955)
2470 compression driver (8676)
2312 horn (1167)
2405 ultra-hig frequency transducer (N/A)

Left
3120A crossover (20325)
2231A low frequency driver (33988)
2470 compression driver (8669)
2312 horn (1189)
2405 ultra-hig frequency transducer (N/A)

Can anyone help me get a little close to what they really are?

[Mr. Widget]

Congratulations! Those look very nice!

If they were mine, I'd put a pair of 2421 diaphragms into those 2470s or sell or trade them for LE85s or 2420s without diaphragms and install new 2421s and then follow the 3133 thread and build custom CC'd networks, or try the Nelson Pass L300 upgrade networks.

Widget

[fpitas]

Here's a link to Mr. Pass's L300 article:

http://www.firstwatt.com/pdf/art_l300.pdf

[4343]

I did the Nelson Pass XO for a pair of SR boxes using 2225, 2461 and 2405. I have to say that the phenolic dias do not really hamper the sound at all due to the tweeter low-pass being just 6db/oct. CC makes it very nice in the mids.

[HCSGuy]

I suspect that what you have started out as a 4320WX, or possibly an empty C50SM enclosure. However, I do not believe that any of your drivers were ever sold as a complete kit in that enclosure. The 2231A didn't come out until after JBL had discontinued that enclosure. Also, as your system is a 3-way, there should be another crossover on the back panel - I suspect there is a homemade one inside the enclosure. I think it's probably most likely that yours started out as a 4320WX and was "Upgraded" through the years - the 2470 would suggest that the original 2420 was blown and someone put in a higher output driver, albeit one that requires a supplemental tweeter. Because JBL raw drivers are so expensive, the way I can see someone justifying replacing all the drivers in the enlcosure is if it was for professional (Studio) use. This is all conjecture, but you definitely don't have any stock JBL configuration. I would look at Nelson Pass's article and build up his crosssover, though it isn't designed for your exact configuration. I would also look for gently used LE85 or 2420 drivers with good diaphragms to try. Enjoy!

[4343]

... I would also look for gently used LE85 or 2420 drivers with good diaphragms to try. Enjoy!

A 2470 is identical to a 2420 with the exception of the diaphragm, so if aluminum is what you prefer, simply replace the diaphragms.

The phenolic is a little warmer, but with a 2405 it's difficult to tell which is which. It would be no contest if both drivers were run flat out, but we're talking rolled off to meet the 2405 at 10K or less.

[MadsKaizer]

I suspect that what you have started out as a 4320WX, or possibly an empty C50SM enclosure. However, I do not believe that any of your drivers were ever sold as a complete kit in that enclosure. The 2231A didn't come out until after JBL had discontinued that enclosure. Also, as your system is a 3-way, there should be another crossover on the back panel - I suspect there is a homemade one inside the enclosure. I think it's probably most likely that yours started out as a 4320WX and was "Upgraded" through the years - the 2470 would suggest that the original 2420 was blown and someone put in a higher output driver, albeit one that requires a supplemental tweeter. Because JBL raw drivers are so expensive, the way I can see someone justifying replacing all the drivers in the enlcosure is if it was for professional (Studio) use. This is all conjecture, but you definitely don't have any stock JBL configuration. I would look at Nelson Pass's article and build up his crosssover, though it isn't designed for your exact configuration. I would also look for gently used LE85 or 2420 drivers with good diaphragms to try. Enjoy!

As I wrote in the the first post, the drivers were collected for a empty cabinet. I also believe myself it is a 4320 cabinet upgraded, I was hoping someone here knew, especially about the cut out for a integrated amplifier as I have not been able to find any information on this.

The priveous owner had the cabinets for over 10 years and slowly collected the drivers to build it up as a 4333, with the larger 2470 and larger horn. Phenolic and alnico components.

As they play good and I am satisfied with them, there is the detail that the 3120A dividing networks split at 1200Hz and the horn is meant for 800Hz, the original shorter horn for the 4333 is meant for 1200Hz.

[hjames]

As I wrote in the the first post, the drivers were collected for a empty cabinet. I also believe myself it is a 4320 cabinet upgraded, I was hoping someone here knew, especially about the cut out for a integrated amplifier as I have not been able to find any information on this.

The priveous owner had the cabinets for over 10 years and slowly collected the drivers to build it up as a 4333, with the larger 2470 and larger horn. Phenolic and alnico components.

As they play good and I am satisfied with them, there is the detail that the 3120A dividing networks split at 1200Hz and the horn is meant for 800Hz, the original shorter horn for the 4333 is meant for 1200Hz.

It still looks like there is only the one JBL Crossover accessible on the rear of the cabinet - guessing that the previous owner built a second crossover that is inside the cabinet to take the high pass signal off the 3120 and split THAT to get a feed for the mid and for the 2405 slot.
(see - http://www.audioheritage.org/vbullet...l=1#post115936)

Not sure that the original 4320s came with a slot for the Energizer (built in Amp module) like the paragons and some other systems did.
I had some 4320s a few years back but I'm not home right now so I can't access my photos to see if I had pix of the backs of the cabinets.

[MadsKaizer]

It still looks like there is only the one JBL Crossover accessible on the rear of the cabinet - guessing that the previous owner built a second crossover that is inside the cabinet to take the high pass signal off the 3120 and split THAT to get a feed for the mid and for the 2405 slot.
(see - http://www.audioheritage.org/vbullet...l=1#post115936)

Not sure that the original 4320s came with a slot for the Energizer (built in Amp module) like the paragons and some other systems did.
I had some 4320s a few years back but I'm not home right now so I can't access my photos to see if I had pix of the backs of the cabinets.

I had the low freq. drivers out of both cabinets last weekend to check the seriel numbers for the registry, there is only the installed dividing network on the inside and all driver wires goes to this, I will have to take a closer look at the divider and see where the HF wires goes inside.

Maybe it is not even a 4320 cabinet, but a D50SMS7 http://www.lansingheritage.org/html/...967-d50sm7.htm

[hjames]

I had the low freq. drivers out of both cabinets last weekend to check the seriel numbers for the registry, there is only the installed dividing network on the inside and all driver wires goes to this, I will have to take a closer look at the divider and see where the HF wires goes inside.

Maybe it is not even a 4320 cabinet, but a D50SMS7 http://www.lansingheritage.org/html/...967-d50sm7.htm

Well, think about it - if there are 3 drivers you need 3 legs on the crossover network(s) Low, Med, High ...
you can't effectively feed the slot tweeter off the midrange freqs.

When i upgraded my pair from 2 way to 3 ways I built the 3133 equivalent network that was listed here -
effectively 4333 spec design ... (drivers not withstanding)

[4343]

Well, think about it - if there are 3 drivers you need 3 legs on the crossover network(s) Low, Med, High ...
you can't effectively feed the slot tweeter off the midrange freqs.

When i upgraded my pair from 2 way to 3 ways I built the 3133 equivalent network that was listed here -
effectively 4333 spec design ... (drivers not withstanding)

If I had to guess, I'd say that there's probably a 1uF cap in the wire feeding the UHF driver. You can get away with that because the mid driver rolls off right about where you want it to, to meet the UHF. You might get a little 10K bump, but it won't be that much. (2470 is spec'ed to "12KHz".)