2441 VS 2421 in 4343 / 4345

[subwoof]

Hey guys...anybody have any experience using the 2311/2441 combo instead of the 2307/2421 in either of the large 4 way monitors?

Since the 2441 is lower in distortion, and the bandwith is easily within it's operating range, wouldn't it be a better choice?

95% of the large systems I install / build use large format drivers and these older 1" diaphrams are getting out of hand price-wise....

I know there are efficiency and impedence issues to deal with but I am looking for crosover tweaks and/or possible other diaphram choices that someone actually has experience using...

Thanx sub

ps - if you go on vacation be aware that heinekens are only 8 oz in aruba and they cost 4.75!!

[Robh3606]

Hello Subwoof

I would look no further than the 4350/55's. Having just had the privelage of listenning to a pair of 4350's I would say Hell Yeh!! Sounds like a good idea to me!


Rob

[Mr. Widget]

I have used both the 1" LE 85 and the 2" 2441 on a variety of horns. In all cases the 2" 2441 sounded less nasal and less harsh. I suggested that Bo do just what you are suggesting with his 4345s. The purist in him wouldn't let him. I do think more improvement would be achieved by using the 2" driver on a horn other than the 2311, but the 2311 is a convenient plug and play solution. Actually I think there would be clearance issues with the larger diameter driver that may require a bit of reworking the interior.

As for electrical compatibility, JBL used to spec the same crossovers for the 375 (2440) and the LE 85 (2420). They also are rated at the same sensitivity. I doubt much tweaking if any would be required. Additionally there is a difference in horn length which some would be concerned with in terms of phase/time alignment. I would argue that in these systems that difference won't be noticeable in most cases as the systems are already all over the map in this area.

Widget

[subwoof]

Hey Mr widget....

I also have seen the "dual" application use on the crossover spec sheets since I started this JBL addiction in the late 70's. I guess proof reading / engineering at JBL was run by the theater crowd in the 60's..

Since these *are* going to be living room only items, I want the lowest distortion ( listener fatigue ) I can get. I will also be running a LOT of power for headroom on these ( biamped )

I also have a number of the 2450 (2"), 2450SL (1.5" w/coated dia ), and 2451H ( 1.5" ) but reworking the baffle in the cabinet shop ( and forever altering their stock status ) is something I haven't decided to do....yet

The metal "array" horn ( 2332 ) that is used in many jbl cabs is a 1.5" 90 degree that has a similar baffle footprint as the 2308 lens. It has an immeiate flare when the sound exits the newer design phase plug and since it's a bit shorter that the 2307, the time align issues ( which were never addressed in the original design ) would be reduced a tiny bit.


I could rout a custom recess for that horn and also make a drop-in plate that has the 2307 / 2311 cutout so the next owner ( over my dead body ) can reuse it in stock format.

sub

[Tom Loizeaux]

Subwoof, It sounds as if you want to do a serious upgrade to the 4343 design. Yes, I think going up to a 2" compression driver would smooth the upper mids a bit and allow for greater SPL. Then, you might want to change the low mid driver to the 12" version because you don't need to reach quit as high when using the 2" driver. Then you might as well add a second 15 to handle the greater levels this system will be able to produce...hey, you've just made a 4350/55!
Seriously, I think the double 15 is a great approach to high level monitors. I also feel the 4343 is a nice balance between ultra smooth output, reasonably high output potential, and modest size. If you don't need to stay with a "coffee table on end" size monitor and want to be able to really crank them, then go for the 4350/55 design!

Tom

[boputnam]

Originally posted by Mr. Widget
...I suggested that Bo do just what you are suggesting with his 4345s. The purist in him wouldn't let him. ... Actually I think there would be clearance issues with the larger diameter driver that may require a bit of reworking the interior.

Actually, that was the limitation - the motor on the 2441 was simply too large to fit into the exact place of the 2421, without modifying the 2122 subenclosure. But, as we've noted here on other Threads, putting a new diaphragm in the 2421 was a great improvement, and reduced the undesireable characterisitics often attributed to the smaller diaphragms.

[subwoof]

Hey tom - all I want to do is lower the distortion and utilize a pair of large format drivers since I have over a dozen pairs here of various types.

I have built and used varaitions of the 4350 for pro uses *but* they require significant EQ and have a longer "working" distance.

I prefer the vertical approach since this room has 12ft ceilings and vertical striped mahogany paneling which matches the 4345's well.

Modifing the 2122 enclosure for the additional diameter wouldn't be that hard since I have had to squish many large drivers into tiny vocal stage monitors over the years.

But I am leaning towards employing removable front panel plates that would allow:

(A) The new 1.5" 2332 / 2450SL combo ( DMS-1 )
(B) The original 2307/2308/2421
(C) The larger 2441/2311/2308
(D) Or a variation: 2311/2330/2451 ( 2330 is a 1.5" to 2" adapter )
(E) Or any "brainstorm" idea that may come along...

sub

[sebackman]

Hi Subwoof and everybody else.

I'm currently building a JBL Synthesis One on steroids. The original Synthesis uses a two 2118, a 2416 and 045Ti for the fronts and smaller stuff for the rest (+ subs). I'm going to use different 8"'s but the important part is going for a 2451J/2332 combo in the mid/high section all around. Above that I'm putting a 025Ti from Ti10K series(or possible a 2404).

Anyway, I have played around with the 2451 and the 2450SL on the 2332 and my findings are that if you do not need the higher frequencies (> 12k as in the DMS-1) the 2451, with non-coated diaphragm may be a better choice.

The 2450SL, correct me here if I'm wrong here, seem to be a coated membrane without the stiffening ribs in a 2451 house. After reading as much as I can find regarding the DMS-1 and other JBL speakers using this combo, my conclusion is that the coating on the SL was really to reduce the “ringing” of the membrane at higher frequencies. It may also give a slightly flatter SPL curve. However it does not appear so below 10-12k in my measurements. At least I cannot reproduce and measure such differences with my MLS system. Above 10-12k they are different and sound different. In a two-way system as the DMS-1 or the old K2’s I would have used a coated membrane.

As long as you are using a tweeter above the driver, as in most 43** monitors, there should be little or no audible improvement using the SL, compared to the normal 2451.

To my personal taste I have noticed a slightly opener and closer sound pattern using the 2451 compared to the SL on the lower ranger of it’s operating area. I can’t show the differences in graphs but it is audible, especially on vocals and pianos. My XO’s are 1k (as the DMS-1 and a result of the horn 2332) and 10k. I use digital active XO’s for now but will convert to passive as soon as time permits.

Best regards

//Robert

[ivica]

As for electrical compatibility, JBL used to spec the same crossovers for the 375 (2440) and the LE 85 (2420). They also are rated at the same sensitivity. I doubt much tweaking if any would be required. Additionally there is a difference in horn length which some would be concerned with in terms of phase/time alignment. I would argue that in these systems that difference won't be noticeable in most cases as the systems are already all over the map in this area.

Widget

May be suggestion to enlarge coil inductance by about 2 times, and reduce the capacitor about 2 times in "low-pass section" of the network for 2420.
so from 0,24mH and 3uF, change to about 0.4mH and 1.5uF, as one of the difference in N3143 and N3155 networks
That would "enhance" high frequency a bit more applied to 2441....