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Thread: Quick & Dirty 4430-Inspired Two-Ways Part I

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  1. #1
    RIP 2011 Zilch's Avatar
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    Quick & Dirty 4430-Inspired Two-Ways Part I

    1) Take B380 w/2235H set vertically on "foot"
    2) Mount 2344A w/2426H/J on top
    3) Cross @ 1 kHz w/CD compensation (M552)
    4) Biamp

    Something I'm missing here?

  2. #2
    Senior Member stevem's Avatar
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    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)?

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    Administrator Robh3606's Avatar
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    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

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    RIP 2011 Zilch's Avatar
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    All RIGHTY, then.

    Quote Originally Posted by Robh3606
    The passive network compensation is simply the best alternative and it's cheap and easy to build.
    The schematic is here:

    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?

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    Administrator Robh3606's Avatar
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    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

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    RIP 2011 Zilch's Avatar
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    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:

    "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."
    It's 24 dB Linkwitz-Riley filters. We'll see. Gonna take an RTA to assess what's going on with these "projects," probably....

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    Senior Member andresohc's Avatar
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    What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?
    Quote Originally Posted by Robh3606
    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

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    Quote Originally Posted by andresohc
    What about the 5233s with 1200 Hz FFBREQ cards. Do they have the same problems as the M552 as far as high freq EQ?
    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

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    RIP 2011 Zilch's Avatar
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    Crossover

    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....

  10. #10
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by stevem
    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.
    Post 'em here in "Marketplace" first with some nice pics. The forum is getting regular traffic these days....

  11. #11
    RIP 2011 Zilch's Avatar
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    I see now what Ian was referring to. The 2344A horn on the 4430 is mounted 1" forward of the woofer baffle, presumably to achieve time alignment. There's certainly issues here, but whether they're major or not remains indeterminate:

    The PH-316 is a 1.5" horn, and using the adapter to convert from 1" to 1.5" adds several inches depth to the assembly. 1/2 wavelength at 1000 Hz is 6.78". Does offsetting the drivers 6.78" and reversing the phase effectively restore time alignment, or just make a mess? What do we line up on the drivers, the top plates?

    Another option is to use a 1.5" driver mounted directly. I've priced 2447 and 2451. They're out of range here. How about 2431? It's a 3" diaphragm driver used in a buncha JBL systems, but I can't locate specs on it. Anybody have a link or know anything about it?

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    There's also the 2430H.

    John

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    What little we know about 1-1/2" 243X drivers:

    3" diaphragm, Neodymium magnets.

    2430 is inexpensive ($246) with an aluminum diaphragm, response to 16 kHz (-3 dB) in EVO sytems, 18 kHz at -10 dB. Also used in PD series systems to 15 kHz at -3 dB. Apparent limited VHF extension.

    2431 is moderately expensive ($399), used in SRX 700 series systems, where it's spec'd to 20 kHz at -3 dB. After a nasty dip around 16 kHz, it hangs on bravely thereabove. Also used in Dance, Array, Vertec and AE series systems. Titanium diaphragm perhaps?

    2435 with Be diaphragm allegedly extending UHF response is HELLA expensive ($1399), more than 2451 (4" diaphragm) variants, even....

  14. #14
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    N200B Voltage Drive. Yellow is L-Pad wide open. Cyan is L-Pad at 50%.
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  15. #15
    RIP 2011 Zilch's Avatar
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    Deja vu?

    Y'know, I could hear N200B sounded better in it's lower operating range. It's why I added the external L-Pad to adjust the balance between the horn and the 2235H. If I crank the network's L-Pad full open, the HF boost is gone, as indicated above.

    3134 & 3135 voltage drive Giskard posted earlier:
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