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santashooter
02-03-2012, 04:48 AM
Hi all, I am currently building a pair of JBL 4345 speakers, but in my gathering of drivers i find myself with a pair of 2307 and a pair of 2312.
I have heard both in other systems, and i have found the longer horn more pleasant in general (not so "harsh") but I guess the longer horn would mean a difference in phasing?:blink:
has anyone in here ever tried a pair of 2312 in the 4345 or know how it would perform and what I should choose.
the reason I ask, is to sell off the pair I don't need, in order to buy a pair of 2405's that I still need.

Of course, it probably ends up with me keeping both, and doing the experiment myself;)

all response is greatly appreciated
Best Regards
Soren from Denmark.

edit: I have tried the search function, but with no luck - though I am aware that it might be my ability to use the search function and not the available information on the site.:dont-know:

Mr. Widget
02-03-2012, 06:43 PM
I don't know if anyone has tried this... I'd be inclined to experiment myself. If you do, please let us know what you find out.


Widget

Amnes
02-04-2012, 11:46 AM
If you find the 2312 superior to the 2307 I'll be happy to become your customer.

santashooter
02-11-2012, 08:52 AM
In order to test the horns, i have to finish my project (obviously), and that is going to take some time.
I am thinking of parting with the 2312 horns, just to finance the 2405 drivers. (got a pair waiting for me)
I must admit i haven't thought it would be so easy to find all the components in europe - has taken me 2 months so far.
and all i need is the 2405 drivers, and they will be mine in the start of march.

But thank you everybody for the response - really love this forum!

best Regards
Soren from Denmark

speakerdave
02-11-2012, 10:20 AM
I think you would be better off going the other way. Use a 2" compression driver and the much shorter 2311. I was able to do this in my factory 4345's using the 2450, although I used the stock crossover and all my evaluation was by ear. 4313B did it in his build using the 2445 and a modified dog box for the 2122. Read his 4345 build thread--he may have modified the crossover also.

4313B
02-11-2012, 11:25 AM
I'm not real wild about the longer delay caused by the longer horn. It sounds smoother in the L300/4333 and that's about the extent of it.

santashooter
02-11-2012, 02:56 PM
I have decided to stick with the original components, along with the original design.
The reason for this is, that originality and JBL's workmanship is really what I try to achieve.
I would like to call the finished product a JBL 4345 - I can't do that if it isn't the original components.
Along with that, I am building these because of a fascination of the stock 4345 - then modification is, for me, just a way to use money.
No intent to pass judgement on other modifiers - I guess its just the way one enjoys his hobby - i am not interested in squeezing the last out of my speakers - but more, I am interested in copying a pair of speakers because I just adore the workmanship and devotion, JBL put into their products.
It's like building a Jaguar E-type - one wouldn't put servo-steering in such a project.;)
On the other hand, It could be fun to see, how fast you can make a Jaguar E-type go.

It is just two different things and two different projects.

So I am parting with my JBL 2312 Horns, and buying the last pieces I need to finish the project.

ivica
02-16-2012, 05:52 AM
I'm not real wild about the longer delay caused by the longer horn. It sounds smoother in the L300/4333 and that's about the extent of it.

As I can remember, crossover point in 4333 is about 800Hz, while in 4345 is about 1300Hz,

so lower frequency=>longer horn(2312, L=11.5"=293mm ???),
while higher frequency=> shorter horn (2307, L=7.75"=197mm, or L=8.5"=216mm)

Just for reminder: 2311 ( 2" horn, L=4.625"=117mm) that was used in 4350/55 over 1200Hz

I was always puzzled about JBL mechanical dimensions....:

http://www.lansingheritage.org/images/jbl/catalogs/1976-pro/page18.jpg
http://www.lansingheritage.org/images/jbl/catalogs/1976-pro/page19.jpg

http://www.lansingheritage.org/images/jbl/catalogs/1978-pro/page19.jpg

http://www.jblpro.com/pub/obsolete/acoustic_lens_family1.pdf

Pay attention the data about 2307 length (from 7.75" to 8.5", or 197mm to 216mm).

May the smaller value is so called "behind the baffle length", the difference is about 3/4"=19mm,

that is usual baffle thickness.



All above "small mouth horns" are used with 2308 Lenses.
I wonder is there any differences in the drivers impedance measured with and without the mentioned lenses-2308.:dont-know: