No, I think you got it. I have something similar I want to sell. Its a 2235H in a veneered 5 cu ft vented enclosure, with a 2426H and 2344A perched on top. I also have high quality cloned passive crossovers (big air core coils and PP caps). Any idea where I can find a buyer (besides ebay)?
3) Cross @ 1 kHz w/CD compensation (M552)
Yes the CD comp doesn't work plain and simple. You need an EQ in that last octave. For PA yes but not at home. The passive network compensation is simply the best alternative and it's cheap and easy to build.
Rob
The schematic is here:Originally Posted by Robh3606
http://www.jblproservice.com/pdf/Stu...ies/4430LR.pdf
I see the subject MF attenuation (L-pad R202 and series R4) and HF bypass (R201 et.seq., 13.5 kHz?) Curiously, in biamp mode, a first-order filter (C7, 20uf, 1000 Hz?) switches in in lieu of second-order (C11, L2) internal passive mode filter. C7 merely provides phase inversion with external crossover, no?
The conjugate filter stays in the LF circuit, as well. Hmmmmm.
The 4430 spec sheet says use 5235 with special board, or, if not, 12 dB/octave at 1 kHz.
Any insights here? Haven't I also seen 5234A with 4430 boards, or are those DIY?
Hello Zilch
Ian had a couple of good post's in this thread have a read.
http://audioheritage.csdco.com/vbull...4430+crossover
That 20uF is one of the poles in the filter and is neccessary when used with the JBL crossovers. The cards are 18db cards not the 12db you would expect. I have a 5235 with the 4430/35 cards same as the 5234 cards.
Rob
I do have a pair of "new" N3134 networks, which I'm going to use to convert a pair of L200's into quasi-4430's, assuming I can make the horns fit. Don't know if anybody here has tried that.
Not sure if I'll change out the LE-85 diaphragms to D8R2425 or just pick up some 2426H's to use, maybe both, for comparison. Depends on what the LE-85's are worth at the time, probably. I'm a little concerned about the baffle angle of the L200's; 2344A in 4430 tuning wants listener on-axis or above, unless that's just BS in the brochure.
Thought I'd try this proposed B-380 "stack," as well. Mackie M1400i has "Constant Directivity" compensation that seems to match what Giskard and Ian posted as being required. JBL M552 has something similar, though I haven't seen the curves yet:
It's 24 dB Linkwitz-Riley filters. We'll see. Gonna take an RTA to assess what's going on with these "projects," probably...."Constant Directivity horn pre-emphasis allows for smooth, flat frequency response from JBL 2360 Series and 2380 Series Flat-Front Bi-Radial horns, or other CD horns."
Hello Zilch
That's a cool idea. You are going to need a 1" spacer board under the 2344 to give it the same baffle alingment as a 4430. I use the M553 with my 2344's and the curve you get is listenable and measures fairly well but after 10K you get a good bit of roll off. The passive network does a better job up top and gives you a way to trim the response which you won't be able to do with the canned CD curve in the M552/553. The Le-85 should work fine figure the original 4430 had 2421's in there. You could go with the 2421 diaphrams but they are rather expensive.
Rob
Well.... what about the sloped baffle? I personally don't think the "Time Alignment" is what makes the 4430s sound good, so it probably won't matter.
Widget
So, is biamping 4430's a worthwhile endeavor at all if you need that passive EQ for the VHF that's in the network for it to work optimally?
And, if so, is there a preference for 5234, 5234A, or 5235 to use with the 4430 cards to do it? Those are 18 dB cards, as I understand it, plus the 1 pole the remains in the passive, makes 24 dB filters, which will be different, at least, from the straight passive use. Enough so to matter?
I've certainly seen posts here attesting to 4430's REALLY shining when properly biamped, tho I've never done it myself. I like 'em plenty good just running passive....
Indeed, the mighty Giskard suggested in an earlier thread, (the genesis of the L200/4430 conversion idea):
"Change the diaphragms to D8R2421's or D8R2425's and let 'em rip."
2421's are diamond surround aluminum, and 2425's are titanium?
What's the difference between 2425 and 2426 drivers, then?
M552 bought on eBay came today, sans manual of course. It appears the "Constant Directivity horn pre-emphasis," whatever it actually is, is there whether you want it or not; I don't see any way to switch it in and out.
Anybody gotta M552 manual they'll copy for me so's I don't have buy one from JBL?
Thank you Ian for the encouragement. If I can work all of this out, converting L200's into quasi-4430's may be a good option for others here. I'm gonna be tryin' the P-Audio horns, as well, as soon at TimG and Widget test them. Guido's earlier work here indicated they were a viable, if not superior, alternative to 2344A's. Thinking I may bring in a couple of skids of them so's they'll be cheap for everyone to try....
The adapter dropping them down from 1.5" to 1.0" adds a couple of inches to the depth, messing up the time alignment, probably. With 24 dB/octave filters, it may not matter. What the Hell, we'll figure a way to tweak it, if necessary. As Widget suggests, it may be only a minor factor in what we like about 4430's, anyway....
What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?3) Cross @ 1 kHz w/CD compensation (M552)
Yes the CD comp doesn't work plain and simple. You need an EQ in that last octave. For PA yes but not at home. The passive network compensation is simply the best alternative and it's cheap and easy to build.
Rob
You can try the 5233 but as Rob says the EQ is best done passively for the 2344. Depending on the woofer or mid driver some tweeking around the crossover is best for smoothest transition.
If you need I we can measure up some coils and chuck ém in the mail for the EQ.
Ian
The optimum "off the shelf" approach for 2344A equivalent horns with 2426H drivers seems to be biamp with 5235 employing the dedicated cards made for 4430/35. From the instructions, it seems easy to make the special cards up if not available.
Supposedly, the same cards work with 5233, 5234(A), and 5235. 5235 has XLR inputs and outputs and a built-in configurable "bump" low-pass filter that might be kicked in to enhance the B380 bass, like BX63, looks like.
In any case, even biamping with external crossover, most of the components of the 4430 passive crossover remain in the circuit.
While I do have a pair of these passive crossovers for experimental purposes, purchasing them to build this project is not a good option. The price is $565 apiece from JBL, if and when available. OUCH!
However, as Robh says, the circuitry is not complex, and it looks like fuctional equivalents are easily and inexpensively assembled DIY, especially if full passive operation is not required. Even at JBL parts prices, the components are much more reasonable at $96.57. Carefully shopped, a full pair could likely be built for less than even that.
Some forum members have already built them, apparently. Perhaps they'll chime in here on the subject with substitute parts lists, prices, sources and pics.
See also earlier 443X crossover work by Guido and Giskard using 2431H here:
http://audioheritage.org/vbulletin/s...ead.php?t=2175
2431H on PH-316 horns is looking like a particularly promising configuration just now.
Progressive Transition Waveguides and OASR horns are on order here, as well. We'll see....
Did you ever complete your work cited above with 2431 and PT waveguides?
I've seen subsequent posts relating to your trying to obtain the square format 100 x 100 version.
Did you ever obtain and test them with 2431?
Can you tell us anything about 2431, like what distinguishes it from 2430?
Is that going to work better than 2426/2344A as supposed?
I'm still desperately searching the square 100x100. They seem to be available in the US. One of you guys should check this.
JBL Part No. is: 338785-002 / PT-H1010HF
I do not believe there is a big difference between the 2430 and 2431. But I do not know this.
If I can get the Horns I'll buy a 2431 or 2430 and give them a try in my (not finished) 4435.
Post 'em here in "Marketplace" first with some nice pics. The forum is getting regular traffic these days....
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