One Last 4345 Dimension Question For You Experts??

[JBLCanuck]

Sorry to bug you guys but I've combed over every forum thread looking for proper blueprints of the 4345 construction & nowhere can I find a post/drawing showing the width of the 2122 doghouse?? I can see that it's 11-1/4"H...6-5/8"D but on none of the drawings can I find the width?
According to my calculations, the outside width looks to be about 15-3/4"...can anyone confirm for me?
I'm forging along...got my foilcals & grill badges on route from Japan :applaud:
Thanks in advance :)

[saeman]

You're not looking in the right place. Go to the Technical Reference Section, System Information, 4345 Enclosure Plans. The info you are looking for is there.

[JBLCanuck]

That's What I've Been Looking For!:applaud:
Thanks Rick.
Sorry for the dumb newbie questions but there's enough info on this site to be reading for a few years. I'm not fond of the search engine on LH...all my searching 4345 threads never brought up any of that post.
That fixes me all up 100% :D
So here's my next newbie question....
When I was over in that area, I read that post by Greg Timbers regarding the 4345's & comparing them to the 250Ti's. He talks about the potential of the big 4 way JBL's when run with an active cross over & the huge improvement that's realized by running a separate amp for the ring radiator. He also says he figures the 2123 is a better mid....has anyone tried it or have any comment?
The 2123's are certainly much easier to come by.
Thanks again for the help :)

[Chas]

I have used the 2123 in my 4345's when my 2122's have been in the shop for reconing. The 4345 network is not optimal for them and they are more sensitive - necessitating tweaking the L-pad levels down, but they did the job, temporarily. With the 4345 network (recapped with Hovlands and biamped at 290Hz)I definitely prefer the 2122, however.

I use the 2123H (biamped at 290 Hz) in my homebrewed modular 434X system using GT's 4344 MkII MF network with a CC'd low pass portion using Solens. The HF and UHF are 2426H/2307/2308 and 2405H. It does work very well with the correct network in this context. I can recommend it highly.

My preference? With the appropriate networks, I love them both. I find the 2123 to be a little more analytical sounding and the 2122 to be somewhat smoother. I could easily live with either.

I hope this helps. Too bad you're so far away, you could A-B them here, if you were closer!:)

BTW: I am pretty sure a 2123 can be reconed as a 2122. Also, the two things I really like about the 2123 are the power handling and there is no foam to rot.

[4313B]

I'm currently working on a several versions that work with various drivers as time permits. It takes time and money because I physically verifiy everything the expensive software suggests.

[Earl K]

BTW Chas, Belated :birthday: !!!


I use the 2123H (biamped at 290 Hz) in my homebrewed modular 434X system using GT's 4344 MkII MF network with a CC'd low pass portion using Solens. The HF and UHF are 2426H/2307/2308 and 2405H. It does work very well with the correct network in this context. I can recommend it highly.

My preference? With the appropriate networks, I love them both. I find the 2123 to be a little more analytical sounding and the 2122 to be somewhat smoother. I could easily live with either.

- I'm still operating under the impression that the 4344mkII was not actually GTs' work ( dimmly based on something Giskard said ). Maybe I need to be straightened out .

- You might just be the first to build that network & state your impressions within this forum . Thanks !

- You dc-biased the woofer but not the rest ? What's up with that ?
- FWIW, I've find that the horn circuit is the place to start ( CC-ing ) / from the perspective of best payoff ( per time & materials invested ) .

cheers

[Ian Mackenzie]

I heard a stock JBL 4344Mk11 (with Steve Kim) sofit mounted in Jazz bar in Japan

It was very nice and the type of system you could spend hours sitting in front of.

http://www.audioheritage.org/vbulletin/showpost.php?p=110349&postcount=3

Getting the 2123h to work right in the 4345 is another issue.

On paper the 2122H has 4 more db output at 100 hertz and its inital rolloff is at a around 267 hertz (ref -1 db)

The 2123H however is like 9 db down at 100 hertz and its inital roll off is like 425 hertz (ref -1 db).

I would be inclined to mess with the box size and try the 2123h in 0.25 ft 3 which provides a more moderate rolloff initial at 375 hertz (ref -1 db) and cross it over a bit higher @ 350 hertz with a 2nd order filter or steeper slope (active). The 4344mk11 used a 350 hertz crossover point. Rob has some practical experience with the 2123H and he might chime in on his experiences.

The low pass passive filter would need re working and the 4344mk11 filter would be a good place to start.

If things come to pass I might attempt the 2123H in my o'l 4345 and see how it goes in the new year just for grins.


Below is a link to GregTimbers comments about the 2122H and 2123H
http://www.audioheritage.org/vbulletin/showpost.php?p=110349&postcount=3

As 4313 says it all takes time for mess with this stuff and often take a lot longer then first thought. But the possibilities are quite interesting though.

[Chas]

- I'm still operating under the impression that the 4344mkII was not actually GTs' work ( dimmly based on something Giskard said ). Maybe I need to be straightened out .

- You might just be the first to build that network & state your impressions within this forum . Thanks !

- You dc-biased the woofer but not the rest ? What's up with that ?
- FWIW, I've find that the horn circuit is the place to start ( CC-ing ) / from the perspective of best payoff ( per time & materials invested ) .

cheers

Thanks Earl. I thought the 4344 MkII was GT's, but I could be wrong. The HF and UHF are Hovland (non cc'd) based, 'cause I had some left over from my 4345's. The HF and UHF are based on the "early" version of the reworked 3145 equivalent network.

I used cc'd Solens for the MF (based on the 4344 MkII network) because they are big assed caps and Solens (even though double the needed value due to the series requirement) were more practical.