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

  1. #346
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    No, it's a conjugate targeted to a specific range. It's designed to reduce the impedance of the resonant frequency of the load. You can see in the graph where is ceases to have an effect.

  2. #347
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    Real impedance above 10 kHz is about 3.5 Ohms, so 2.2 uF HP is rolling down from above 20 kHz, as you showed last night.

    My 2.0 uF is starting even higher, so me getting the right value in there may lift the dip at 1 kHz a bit.

    I'd imagine being off by 10% in this matters, if not considerably. We'll see when the right parts get here....

  3. #348
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    Ok. You can see from my graph that both runs are at ~ 3.5 ohms at 10 kHz so we seems to be in agreement there.

    Yes, the 2.2 uF should increase the output a bit.

    How does it actually sound right now though?

    Cyan shows the voltage drive with a 3.5 ohm load rather than 8 ohm load.

    Magenta shows the 2.0 uF with a 3.5 ohm load. It looks like the 2.2 uF is worth roughly 0.84 dB across the bandwidth.
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  4. #349
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    Quote Originally Posted by Giskard
    How does it actually sound right now though?
    They are balanced, clear, with crisp (even sibilent) highs. They're on a platform truck about 4 feet out from the wall with "stuff" behind them, so boundary effect and room response would enhance the bass in a normal listening environment. I can hear it's there aplenty.

    Not as transparent as true 4430's, they're more like big 4425's.

    I've come to rely substantially on RTA for setup and performance evaluation; if it says they're within +/- 2.5 dB, I'm done. Attempting to tune better than that in this room (garage) is fuitless.

    I have an L-Pad on the HF, but it's been at full on ever since I hooked them up. They're set up for biamping, too, and if I REALLY want to dial them in, I could use the UltraCurve....

  5. #350
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    So then, not bad for a minimal network eh?

  6. #351
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    Simple counts BIG around here.

    If it can be said that I have an angle, it's "simple."

    Most folks don't have an LCR meter to tune custom inductors, or an RTA to test the results. Virtually anyone can make a set of these and enjoy the outcome.

    Something this cheap and easy to build from stock components that plays this well definitely gets the Zilchster DIY Seal of Approval.

    B380 - BYO
    2235H - $300
    2426H - $200
    2344A - $220
    N200T3-$80

    TOTAL - $800/pair

    Satisfaction from having built 'em yerself - "Priceless."

  7. #352
    Senior Member Guido's Avatar
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    Quote Originally Posted by Guido
    Yep, 2416 has resonance peak at 1,4 kHz, 2426 at 1,1 kHz. I'll dig my impedance curves out.
    Here are some impedance plots.

    First pic
    2426 on 2344 with D16R2421 (red), D8R242h (blue) and 2420 on 2344 with D162421 (orange).

    Second pic
    2418H on 2342 (red), 2416H on 2342 (blue)
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  8. #353
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Zilch
    1) With HF conjugate
    2) Conjugate disabled

    It's working at 15 - 20 kHz looks like, doin' the HF boost?

    Maybe some action down at 1 KHz, as well.

    [Very clevah.... ]

    The relevance is that for $72.76 a pair and a couple of hours breadboarding time, these little crossovers are credible performers with the "Quick & Dirty" combo using 2344A horns on 2426H. They'll likely work even better than I have demonstrated with the proper 2.2 uF caps in there, and with Guido's impedance curves, we may be able to "tweak" them a little more.

    Apparently, they'll work for 4425 clones as well, using 2342 horns and the smaller 241XH drivers. Sounds like RobH's maybe gonna try that....
    Am I missing something here? Aren't you concerned about being about 10dB down at 1.25KHz compared to 10KHz or am I reading your plots incorrectly?

    Widget
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  9. #354
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    Naw, 'cause the woofer plays there too. There's a dip a little higher, tho....

    http://audioheritage.org/vbulletin/a...tid=6583&stc=1

  10. #355
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    Quote Originally Posted by Zilch
    I have an L-Pad on the HF, but it's been at full on ever since I hooked them up.
    Which raises an issue: Stickin' anything other than maybe a 4-Ohm L-Pad immediately ahead of the driver's gonna shift the rolloff frequency around, since the HF network wants to "look into" 3.5 Ohms. "Nominal" 8-Ohm L-Pad would move it down a full octave, worst case, at max attenuation, no?

    Alternatively, you'd have to know and match the network impedance to put one ahead of it, as well?

    [Maybe I'm over-thinkin' this....]

    EDIT: Hooked up a 3.5-Ohm resistor to an 8-Ohm L-Pad. Indeed, it varies essentially linearly from 3.5 Ohms at full on to 8.5 Ohms max at about 80% attenuation. It'd take some fancy writing to make that a "feature."

  11. #356
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    Build something like a 3-position switch with fixed resistors. Something like 0 dB, -1 dB, -2 dB.

    You could also get an L-Pad to work between the 2.2 uF capacitor and the 1.0 mH (7.5) inductor and then adjust the value of the 2.2 uF accordingly.

  12. #357
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    New arrivals:

    Along with Guido's PTH waveguides, a new pair of 2431H drivers came in. I mounted them in the modified L200's on PTF waveguides. No EQ, just the AM crossovers we're using, here's the performance, L & R:

    Get OUTTA here!!!
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  14. #359
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    C'mon, Giskard,

    Build yerself a pair of these using LE14H-1 ('cause I've got your 2235H's, now. ) They could be KILLER!

    [AND, you could help us tweak this combo, first hand. ]

  15. #360
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    Oh it's tempting!

    I've still got my 4430 horn/cd combos and managed to pick up a 3rd NOS horn not long ago for a center channel... still looking for a third perfect 2425H...

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