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Thread: 2447J/2381 For home HiFi

  1. #1
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    2447J/2381 For home HiFi

    I recently got a great deal on a pair of 2447J drivers on 2381 horns. They are mint I was wanting to use these in a home HiFi setup. My thought was to build a tower with 2 15's and the horn in the middle. I am at a loss though on what woofer to use? I want good low end and not have to use a sub. Also should I run the horn down to 500Hz? I supose that depends on what woofer I use. 2226H, 2235H,?? Any Ideas would be great.

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    anyone?????

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    Senior Member grumpy's Avatar
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    pair of 2234's (4435 style augmentation) <- what I'd probably do.
    pair of 2235's (4355 arrangement)
    pair of LE14H-x ? ... haven't heard a pair of these together.

    My preference leans toward those types of drivers vs 2226 in my living room.
    I'd also suggest you try a crossover range 800-1000Hz, even with the large
    diaphragm driver.

  4. #4
    Senior Member Rudy Kleimann's Avatar
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    Due to their relatively short height, those horns lose control of vertical dispersion below 2-2.5 KHz As you go down in frequency, they act more like a diffraction "slot" than a horn in the vertical plane. They do better in the horizontal plane, but lose control below about 1-1.2KHz, again due to their width. Keep going down in xover freq., and eventually the horn is unable to load the driver or contriol dispersion at all, and they sound really bad -and can destroy the diaphragm being pushed with much power below this point due to over-excusion driving the diaphragm to strike the phase plug.

    What'll happen is they'll sound "Honky" as you go down in frequency, beginning around 2KHz and getting worse as you go down. On the other hand, the midrange drivers starts at the lowest frequencies with more or less hemispherical (180*) dispersion (depending upon how large the speaker cabinet's front baffle is) and dispersion narrows as you go up in frequency relative to the cones diameter. For example a 10" cone has a dispersion pattern of about 90* conical at 1.2-1.5KHz. The 2381 behaves as roughly a 90*x90* horn in this frequency range, so the transition from mid to horn sounds pretty good. The further up you go in crossover frequency, the "beamier the midrange gets. They horns output will spread out much more around the listening area than the mid, and it will sound really bright and "honky", especially when listening from a position off to the side instead of directly in front. If you run the mid to horn crossover frequency to too high a frequency, the upper mids from the cone will sound weak, particularly listening off-axis; cross over too low, then turn down the horn to match the dark-sounding mid, the highs above .5KHz will sound weak.

    It's a juggling act...

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    hmmm maybe this driver isnt the best choice for home use. I just hate to let it sit around. Maybe I will just pair them back up with the 2226Gs for SR use.

  6. #6
    Senior Member Rudy Kleimann's Avatar
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    Well, I wouldn't SAY THAT...

    Give 'em a listen. Depending on what you had before, they might be the best thing you've ever heard!

    There is no perfect driver; believe me I know. You just gotta know how to work 'em. Zilch knows these drivers too; start reading his related threads from the last three years. More than you need to know right there.

    How were you going to cross them over and EQ them? You can build a passive EQ/crossover- there are many, many JBL production models that use the 2447/2381 that you could use the internal xover schematic as a template. If you're a tweaker, you could go from there. Or, use something like a DBX DrivRack PA (about $500new or $300 used, add calibrated mic for another $100) or the Behringer auto EQ/crossover/delay/swiss army knife for under $300 new. Zilch has been using one for a couple years now.

    To clarify, don't cross them over below about 1.2KHZ if you expect the 2381 to act like a horn instead of spreading out all over the room below that. And definitely don't run them down much below 800 Hz- the horn will not load the driver properly. While it's unlikey you could stand the SPL it would produce before damaging the driver in your home, the frequency response and dispersion down low like that would be crazy, especially when you factor in room reflections, unless the room is really "dead". But since you have them, try it out. If you stil have them in the factory cabinets with the 2226, hook 'em up! What do you have to lose? If the unit is biampable, try that too.That way you'll know what happens from crossong over higher or lower, and learn something about speaker design
    Last edited by Rudy Kleimann; 08-05-2008 at 06:04 PM. Reason: added last paragraph

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    I have a DBX driverack, I ran them in the stock cabs with the 2226Gs in biampmode. I ran the horns down to 500hz at pretty low volume and yeah it was horible. I will keep them around 800 to 1.2k when I decide on a woofer other than the 2226G. The only reason I am going away from the 2226G is lack of bass response. Is this b/c the spider is so stiff or lack of foam surround. All I want is a slaming home speaker that will flat out just get loud and have low end. no HT or really good sound quaility is needed for these.

  8. #8
    Senior Member Rudy Kleimann's Avatar
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    Both. Stiff and foam surrounds are more or less contradictions, but the spider (inner suspension at the Voice coil) is part of the picture. Cabinet size too.

    What you need is something like what the guys above suggest, or a sub and a mid, if you want deep bass and need to go up to meet the 2247/2381's range.

    Myself, I have a pet project I'm going to build one of these days using a 2012H from 300-1.2 or so, and 2447 on either a 2381 or the bigger 2352 horns I happen to have, above them. A 2447 don't sound so spectacular above 8KHz, so I'll need something to finish off the top cleanly to beyond 20KHz. I have everything except the very top already. The bottom end is another question altogether for me too. I have some JBL cabs with dual 15" 2035's from a movie theatre, made out of particle board, which would easily be destroyed using them for PA gigs.

    Lately I've been thinking of trying out a BMS 4"+ring radiator coaxial compression driver on the big JBL2352 horn. Rumor has it that the new JBL ring radiators are BMS designs that JBL licenses to build here, and that's a good sounding UHF driver. The 2352 holds its Vertical and Horizontal pattern control extremely well down to below 1KHz, and fully loads the driver down to below 630Hz. I may even be able to run a pair of 15" or the right 18" up to meet the horn and end up with a three-way system, which would simplify design and tweaking considerably.

    I too have a couple DriveRack PA's and the mic, and plenty of amplifiers to do the job.

  9. #9
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Rudy Kleimann View Post
    Myself, I have a pet project I'm going to build one of these days using a 2012H from 300-1.2 or so, and 2447 on either a 2381 or the bigger 2352 horns I happen to have, above them. A 2447 don't sound so spectacular above 8KHz, so I'll need something to finish off the top cleanly to beyond 20KHz. I have everything except the very top already. The bottom end is another question altogether for me too. I have some JBL cabs with dual 15" 2035's from a movie theatre, made out of particle board, which would easily be destroyed using them for PA gigs.

    Lately I've been thinking of trying out a BMS 4"+ring radiator coaxial compression driver on the big JBL2352 horn. Rumor has it that the new JBL ring radiators are BMS designs that JBL licenses to build here, and that's a good sounding UHF driver. The 2352 holds its Vertical and Horizontal pattern control extremely well down to below 1KHz, and fully loads the driver down to below 630Hz. I may even be able to run a pair of 15" or the right 18" up to meet the horn and end up with a three-way system, which would simplify design and tweaking considerably.
    Techbot recently posted the first confirmation of a BMS connection that I've seen:

    http://audioheritage.org/vbulletin/s...ad.php?t=21754

    2408 is different, but may be under license.

    2452H-SL has the extension 2447H/J lacks, plus Aquaplas-damped smoothness. I've run them on 2381 and 2352, and both of those combinations are top tier, in my experience.

    Two-way's easier, and better if you can make it happen....

  10. #10
    Senior Member Rudy Kleimann's Avatar
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    Let's talk about the 2452H-SL

    True that- less IS more. Less work, less transition problems between drivers at crossovers, all that.

    RE: 2452-SL- what distinguishes it from the 2447, besides the diaphragm? I expect it is a Neo magnet, but is the phase plug different too? Can I expect nearly the same performance with the 2452H-SL diaphragm in my 2447 motor assy? If not, have you tested this combination and compared the two?

    I'd love to find the one driver that could carry from 1.2 -1.6K and go all the way up without the ridiculous and complex EQ the 2447 would require -and the ugly sound above 8-10K that would be a part of the formula w/ 2447.

    I cooled off on this project after getting burned on ebay last year for three 2435HPL's by the same seller that burned fellow German LHS member rs237. (You may recall my PM's to you about this) On paper, at least, it was much better than the 2447 or 2451, but still fell short of 20K.

    RE: BMS- I was enlightened by the US importer of BMS to the licensing to JBL for their ring radiator. FWIW- He also said that JBL could never get the performance of their own driver quite up to the level of the German-made BMS model due to production problems in diaphragm manufacturing.
    The 2452H-SL sounds alluring... please post any links to threads or posts of your "R&D", particularly compared to 2447 w/2450 dia and especially a 2447 w/2452H-SL dia.

    Thanks!

  11. #11
    RIP 2011 Zilch's Avatar
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    The sum total of my experience with 2447s is measuring several for Johnaec, who turned me on to 2381s in the course of doing that. I put 2452H-SLs on them and didn't look back.

    One of the first things I did was mount them on H9800, a most memorable episode in these forums.

    Seems like Subwoof is the member next most familiar with using them here. I've posted most of my work with them in other threads, and "Search" should find that easily....

  12. #12
    Senior Member Kalle's Avatar
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    I have speakers with 2447/2381 and the sound a little harsh and hard. Would my problem be solved with aquaplas diagrams? In what I can read if changing the diagram in 2447 to aqua it would sound like a 2452sl? I can get D16R475ND aquaplas for 475 that fit my 2447 for right price. I quess that tey are better than the 2452ls dias tho they are made for JBL K2 S9500?!

    I quote zilch in this tread:
    "2452H-SL has the extension 2447H/J lacks, plus Aquaplas-damped smoothness. I've run them on 2381 and 2352, and both of those combinations are top tier, in my experience."

    So what do youy think?


    /Karl

  13. #13
    Senior Member ivica's Avatar
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    Quote Originally Posted by Zilch View Post
    The sum total of my experience with 2447s is measuring several for Johnaec, who turned me on to 2381s in the course of doing that. ...
    http://www.audioheritage.org/vbullet...l=1#post166172

    http://www.audioheritage.org/vbullet...l=1#post166177

    regards
    ivica

  14. #14
    Senior Member Lee in Montreal's Avatar
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    Hi Club

    I suspect that your goal wass to build a two-way system (5 years ago ;-) ). I congratulate you for wanting to make simple, vs the trend of 4 ways speakers ;-)

    After years (well, decades) of experimenting, I think I found my new resting place. I built a two-way system a few months ago and I can't stop being impressed. My system is currently a 2-way + sub, but intend to keep it a true two-way in the coming months.

    I currently run a JBL 2360 horn and 2445 driver from 500Khz and up. At the bottom, the current set-up consists on a JBL 2226. It sounds great when properly equalized at its bottom end. Ideally, it should be replaced by a two 2235 or 2234. The ideal system would therefore be two 15" woofers and one horn and 2" driver. Two-way system usually sound thin. This one is literrally a wall of sound, thanks to the big horn.

    To help the bottom end (20Hz to 50Hz), I run a 2245 sub. But if I had two 2235 (or 2234) per cabinet, I wouldn't need the sub.

    http://img.photobucket.com/albums/v6...ps7f020e8a.jpg

    http://img.photobucket.com/albums/v6...psf9920f88.jpg

  15. #15
    Senior Member Kalle's Avatar
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    Hi!

    Actually that dosen`t tell me very much about my question. My enlish is not the best so im not sure I understand what you mean. What should I do about the not very nice sound from my 2447/2381 mids? I use them for HIFI at home. Will the aqua help me? The driver should be like a 2452sl with that I think.

    Regards
    Karl


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