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Thread: New Project : DIY 4438

  1. #1
    Senior Member Ralf's Avatar
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    New Monitor Project : DIY 4438 Dual 18"

    I think at present about a possibility of achieving deepest frequencies, max. pressure and natural sound .
    I could be inspired from the 4435.

    Here is a first study with two 2242H, one 2234H and the 2344A/2426...
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    16 Hz can not be substituted

  2. #2
    dancing-dave
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    I can just hear that speaker going "WHUMP!"

  3. #3
    Super Moderator Hofmannhp's Avatar
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    4438

    Quote Originally Posted by Ralf
    ....with two 2242H, one 2234H and the 2344A/2426...
    Hi Ralf,

    nice idea.....but what's the job for the 2234? When crossing the woofer section to the 2344 with about 1 kHz, for my opinion the problem may be the 800 - 1kHz. I would prefer a 10" or 12" for the lower mids, with less cone distortion in this frequency area... think about to use a 2441 with a good horn and try to set the crossover frequency to the woofers to 700-800 Hz. An additional 2405 maybe also give a fine and "crispy" sound.

    (only my "1 cent")

    HP
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  4. #4
    Senior Member Ralf's Avatar
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    Quote Originally Posted by Hofmannhp
    Hi Ralf,

    nice idea.....but what's the job for the 2234? When crossing the woofer section to the 2344 with about 1 kHz, for my opinion the problem may be the 800 - 1kHz. I would prefer a 10" or 12" for the lower mids, with less cone distortion in this frequency area... think about to use a 2441 with a good horn and try to set the crossover frequency to the woofers to 700-800 Hz. An additional 2405 maybe also give a fine and "crispy" sound.

    (only my "1 cent")

    HP
    Hi Hans-Peter,

    I would cut off the both 2242 at 100 Hz or less. So it makes sense with an additional driver for the lower mids. Why you thing it`s a problem to cut the 2234H at 1k? it`s the same situation as in your 4435...
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  5. #5
    Senior Member Ralf's Avatar
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    What Horn????

    The 2344 isn`t available on the market. I have only one at the moment.

    Is it possible to get the new OASR horn? Driver should be 2417???

    Or what is with the 2451H? What horn could be used? Questions over questions...




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  6. #6
    TimG
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    I'm currently waiting for an adapter so I can measure the P Audio pseudo clone of the 2344 with a 2426H and should have results in about a week. I'll simulate a modified 4430 crossover to use it with my 2234H and I can post a schematic. The 2451 has a 1.5" throat so any of the horns used with the 2430 could be used with this driver. You can get a 2381 or 2383 horn directly from JBL to use with this driver http://www.jblproservice.com/pdf/Hor...%20List%20.pdf but it does not have response all the way to 20kHz. You would probably want to add a supertweeter above 10kHz. I also know where you can buy some barely used 2451s for $450.

  7. #7
    Senior Member Ralf's Avatar
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    Considerations

    ok. what we have now:

    2 x 2242H
    active Network for the 2242: modified 5235A with BX6 tuning

    1 x mid bass driver ??? Guido has suggested the 2123H?

    1 x 1,5" horn ??? maybe with 2451 neodymium driver

    1 x 2405 passive network starting from 10kHz


    @TimG: isn`t it that the 2344 clone is a 1,5" horn?

    @all: has anybody hear the OASR horn?
    What you think about this idea?
    16 Hz can not be substituted

  8. #8
    Super Moderator Hofmannhp's Avatar
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    4438

    [QUOTE=Ralf]...... Guido has suggested the 2123H?
    ......1 x 2405 passive network starting from 10kHz ....
    QUOTE]

    Hi Ralf,

    that sounds fine to me.....

    for my opinion the 2234 in your first assy has not very much to do in the frequency range it is built for and the 2123 can handle the lower mids a lot better. Congratulations for your decision to take an additional 2405 (in this frequency range also the 4435 needs assistance)

    HP

    (PS: next weekend (sat 7:00pm and sun from 2:00pm )we celebrate a small xmas fest in my garage, opened for all to come .....if you like, ...and please tell it to Guido)
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  9. #9
    RIP 2011 Zilch's Avatar
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    Mid-bass? 2206, of course. Gotta keep up with those dual 18's.

    I, too, am hoping Tim will find opportunity to try the 2344A clone with a 1.5" driver like the 2451 suggested. Does it provide any VHF extension?

    It is, indeed, 1.5", but adapts down to 1" for 2426.

    I KNOW y'all like the 2405 for UHF, but 2404 would be a better match for 2344 mids, no? The one occasion I have seen 4435 "enhanced" with a supplemental UHF drivers, that's what was used....

  10. #10
    Senior Member Guido's Avatar
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    Quote Originally Posted by Ralf
    ok. what we have now:

    2 x 2242H
    active Network for the 2242: modified 5235A with BX6 tuning

    1 x mid bass driver ??? Guido has suggested the 2123H?

    1 x 1,5" horn ??? maybe with 2451 neodymium driver

    1 x 2405 passive network starting from 10kHz


    @TimG: isn`t it that the 2344 clone is a 1,5" horn?

    @all: has anybody hear the OASR horn?
    What you think about this idea?
    Low Mid 2123H or 2012H

    1,5" PAudio PH-316 (2344 clone), see:
    http://www.audioheritage.org/vbullet...&highlight=316
    I would go with the 2430

    I would suggest only on active xover. Low mid, mid and high should be passive!

  11. #11
    Senior Member Ralf's Avatar
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    Quote Originally Posted by Zilch
    Mid-bass? 2206, of course. Gotta keep up with those dual 18's.

    I, too, am hoping Tim will find opportunity to try the 2344A clone with a 1.5" driver like the 2451 suggested. Does it provide any VHF extension?

    It is, indeed, 1.5", but adapts down to 1" for 2426.

    I KNOW y'all like the 2405 for UHF, but 2404 would be a better match for 2344 mids, no? The one occasion I have seen 4435 "enhanced" with a supplemental UHF drivers, that's what was used....
    Hi zilch,

    look at my avatar. I tested both the 2405 and the 2404 with 2344/2426J and what you think is inside now?
    Right! The 2405. It has the "crispy" (HP`s definition) sound and that is what I prefer. But everybody has an other taste...

    For the mid bass: this is the most important part of the system. I use the 2206 in my blue tops for party employment because I wanted most power compression. But in this system we need a driver which is more linear...
    16 Hz can not be substituted

  12. #12
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    Hi Ralf

    If it was my project, I'd focus on upgrading all the chosen cone drivers to JBLs' 1/2" deep-gap types. To my ears they offer "truer and tighter" resolution .

    The challenge if you go this route will be to design in circuit compensations to deal with the typically "rising" frequency response curves that these newer drivers have . It's a hassle - but I believe it's well worth the effort .

    I prefer 10" drivers over 12(s) so that would have me chosing the 2012H or the 2251j. I usually match 1, 18" to a 10" or 12" to give you an idea of how many components I might be looking at .

    For my ears, this much "paper down below" might excuse the 3" diaphragm, for a substitution by the 4" driver and its' extra midrange resolution. . Yes, a tweeter of some sort would be required . This would end up being more of an evolution of a higher resolution 4-way ( 4345 ), rather than a build up of a super 2.5 way, ( such as the 4435 ) .

    In my opinion , it's all about matching the subjective resolutions of the various components .

    regards <. Earl K

  13. #13
    lfh
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    What about 2202 for mid bass? Together with the dual 18" bass drivers, a 2441/2311/2308 combo and the 2405, one could build a "super 4355" (possibly with another baffle layout, though).

    Just my EUR 0.02

  14. #14
    Senior Member Ralf's Avatar
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    Update

    I`ve read the data sheet of the 2123H and compared it with other drivers.
    Mmmmhh...that could be a fine choice for this project or not???

    Earl has suggested e.g. the 2251j. But I can`t find spec sheets for this new drivers...
    Has somebody more informations?

    So here is the provisional update:

    2 x 2242H ???
    active Network for the 2242 A : modified 5235A with BX6 tuning 20-80Hz
    active Network for the 2242 B : modified 5235A with BX6 tuning 20-350Hz???

    But what is with the 2243??? I've seen the thread about it in the moment....the specs are interesting:

    JBL 2243H
    The 2243H uses the 2242H basket and has a foam surround.

    Fs = 30 Hz
    Qms = 5
    Vas = 338.1 liters
    Cms = 0.155 mm/N
    Mms = 0.182 kg
    Rms = 6.854 mohms
    Xmax = 5 mm
    Xmech = 10 mm
    P-Dia = 397.4 mm
    Sd = 0.124 sq.m
    P-Vd = 620.1 cu.cm
    Qes = 0.2
    Re = 5.2 ohms
    Le = 1.4 mH
    Z = 6.24 ohms
    BL = 30.2 N/A
    Pe = 700 watts
    Qts = 0.19
    no = 4.401 %
    1-W SPL = 98.58 dB
    2.83-V SPL = 100.5 dB

    ...we should discuss about it....


    1 x 2123H??? active low cut 350Hz - ~1200Hz or maybe a newer one with neodymium ???

    1 x 1,5" horn ??? maybe with 2451 ??? neodymium driver passive network with EQ 1200Hz - 10kHz

    1 x 2405 passive network starting from 10kHz

    urgggh...now I know nothing but we want to have a dual 18" with a 10 or 12" mid bass driver, a mid horn and a super tweeter

    I am pleased about further suggestions.
    It would be also nice from you, if you have some links to the appropriate data sheets. Some new driver specs are hard to find...
    16 Hz can not be substituted

  15. #15
    RIP 2009
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    To keep things current, I think you'll find lower distortion in the 2012H than the 2123H, (I've also heard it rumored that the 2123H curve is not as flat as published), and maybe the 2332 horn with the 2451H driver?


    John

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