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Thread: D2430K compression driver information?

  1. #16
    Senior Member pos's Avatar
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    Quote Originally Posted by macaroonie View Post
    It runs out to 30 K ish without compensation
    Are you sure about that? I am sure the mass breakpoint is very high in frequency, but there will always be one, and much lower than 30khz I guess. So ultimately compensation will always be needed when used on a constant directivity horn, at some frequency...

  2. #17
    Senior Member macaroonie's Avatar
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    Pos , I did a LOT of digging on this driver and the info is there if you care to look. Chase down VTX boxes and you will find all you need to know. I'm pretty certain it's 30K ( might be - 6 or -10 in fairness ) The main thing is that the driver seems to play well beyond ' normal' mass break points. Remember the dias are very small by comparison with conventional types and I suspect they have achieved very high compression ratios.
    Read more my friend , its fascinating.

  3. #18
    Senior Member pos's Avatar
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    Yes I have read the articles linked in the other thread, but nowhere have I found any tube measurements for example (VTX box measurements account for EQ that compensate the rolloff).
    So it is is difficult to assert any mass breakpoint before Techbot gives us the EDS

    I have some 2407 ring radiators (direct BMS knockoffs), and even with the tiny radiating surface and ridiculous MMS it still has a mass breakpoint, and not that higher than other drivers...
    So far the 2435 (without aquaplas) is the driver with the highest mass breakpoint that I know of (excluding supertweeters), and it is still nowhere near 30khz, nor 10khz.

  4. #19
    Senior Member macaroonie's Avatar
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    As I said , somewhere in the online info , including You Tube , there is mention of the driver extending out to 30K
    Clearly absolute tech info will be kept under wraps till the patents are granted.
    I don't blame them , this would seem to be cutting edge innovation. Thats probably why they gave the nice Russian gentleman a job.
    I can readily see this driver format becoming much more familiar in the future. The current offering is operating at the extremes of the parameters , power etc. The compliance will need to be on the stiff side to cope with the incoming signal. Come back down to domestic and or small ' studio ' requirements and a lot of mechanical aspects can be smoothed ,softened or refined.
    4313 is correct in that this is a working tool meant to get very loud , all day , every day.
    Not necessarily ideal for domestic use.

  5. #20
    Senior Member pos's Avatar
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    Quote Originally Posted by macaroonie View Post
    there is mention of the driver extending out to 30K
    Ok, but that does not say anything about the need (or lack of) to use compensation (EQ) to reach that point.

  6. #21
    Senior Member macaroonie's Avatar
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    http://www.youtube.com/watch?NR=1&v=1JWg1icrqn0

    Mark Gander at 1m50s Admitedly unqualified statement

  7. #22
    Senior Member pos's Avatar
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    He talks about a smooth response without breakups (thanks to the small mylar ring diaphragm), nothing about mass breakpoint or compensation EQ

  8. #23
    Senior Member ivica's Avatar
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    Quote Originally Posted by pos View Post
    He talks about a smooth response without breakups (thanks to the small mylar ring diaphragm), nothing about mass breakpoint or compensation EQ
    Hi,

    May be attached figure can explain all the words about the F-R.

    http://www.diyaudio.com/forums/attac...esp8502f17.pdf

    It seems to me that at LF section Xmax limitation make D2430K less efficient but on the HF section it outperforms 'dome' model. Unfortunately the distortions were not shown.

    Very nice technical explanation can be find in :

    http://www.google.com/patents/US20110085692

    http://www.google.com/patents/US8280091

    regards
    Ivica
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  9. #24
    Senior Member pos's Avatar
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    Quote Originally Posted by ivica View Post
    It seems to me that at LF section Xmax limitation make D2430K less efficient but on the HF section it outperforms 'dome'
    Interesting measurement, thanks.
    (1, red) is the dual driver. It peaks in midband, then rolls-off earlier than the dome metal, and then goes up and extends a bit further after 20khz (but the horn is not CD anymore at those frequencies).
    Looking at those measurements it *looks like* the D2430K mass breakpoint is in fact lower in frequency than the one of a titanium dome compression driver

    My 2407 exhibits a similar behavior in the UHF, and published curves are similar: JBL, BMS.
    Distortion measurements of the D2430K would be interesting indeed, but one can expect the 2nd order distortion to be lower than single ring radiator drivers thanks to the dual push pull diaphragms (even order distortion cancellation...)

  10. #25
    Senior Member pos's Avatar
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    Here are the crossection settings from the M2 preset for the D2430K on the M2 waveguide, published by 4313B:



    and together with the (1st order electrical!) crossover and global EQ:


    So obviously it *needs* EQ to reach UHF on a constant directivity device: around 10dB between 2kHz and 9kHz. Above 9kHz it seems to keep its level up to 20kHz (and maybe above), which is a phenomenon that already partially appears on the 2407H and other BMS designs.

    Lets wait for distortion measurements now, to see the effect of that push pull design on 2nd order distortion! (which was the big drawbacks of BMS designs...)

  11. #26
    Senior Member ivica's Avatar
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    Quote Originally Posted by pos View Post
    Here are the crossection settings from the M2 preset for the D2430K on the M2 waveguide, published by 4313B:



    and together with the (1st order electrical!) crossover and global EQ:


    So obviously it *needs* EQ to reach UHF on a constant directivity device: around 10dB between 2kHz and 9kHz. Above 9kHz it seems to keep its level up to 20kHz (and maybe above), which is a phenomenon that already partially appears on the 2407H and other BMS designs.

    Lets wait for distortion measurements now, to see the effect of that push pull design on 2nd order distortion! (which was the big drawbacks of BMS designs...)
    Hi pos,

    It is interesting that only several dBs compensation is really needed ( points 6. , 7. and 8.) to compensate almost much deeper ( over 10dB) notches on the driver 'alone' response. May be some improvements have been done after serial production established.

    Regards
    ivica

  12. #27
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    So obviously it *needs* EQ to reach UHF
    Not really any different than the 476Mg on the H9800 horn or the PT waveguides. If I remember correctly, a 6 dB shelf above 6 kHz in those instances.

    Of course the 476Mg is, for all intent and purpose, unobtainable.

    JBL is also nit picking with respect to the M2, obviously they wanted that curve as flat as possible to wow the graphophiles. The K2 and E2 have only a few notches amongst them. They could be cleaned up significantly if desired.

  13. #28
    Senior Member ivica's Avatar
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    Quote Originally Posted by ivica View Post
    Hi,

    May be attached figure can explain all the words about the F-R.

    http://www.diyaudio.com/forums/attac...esp8502f17.pdf

    It seems to me that at LF section Xmax limitation make D2430K less efficient but on the HF section it outperforms 'dome' model. Unfortunately the distortions were not shown.

    Very nice technical explanation can be find in :

    http://www.google.com/patents/US20110085692

    http://www.google.com/patents/US8280091

    regards
    Ivica
    Some additional information can be find:

    http://www.fohonline.com/images/stor...0.200.1202.pdf

    measurements done with 1.5-inch plane wave tube.

  14. #29
    Senior Member macaroonie's Avatar
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    Some more D2 info

    http://www.google.co.uk/url?sa=t&rct...52109249,d.ZGU

    Download the pdf.

    One snippet it directly describes and has a diagram for a 1.5" coil version

  15. #30
    Senior Member pos's Avatar
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    Interesting thanks!

    10 pages left to find
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