JBL Array 2235 Be project

Discussion in 'DIY Discussion' started by cooky1257, Sep 17, 2009.

  1. cooky1257

    Dev Moderator

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    They are in the wrong house? :D.
     
    Dev, Sep 30, 2009
    #41
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  2. cooky1257

    cooky1257

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    Hi Joel,
    Mmmm, they are pistonic to 15khz, anything past 14khz is not the best uhf around tbh hence the tiny 045be/ti comp drivers.
    I actually roll them off above 13.5khz(@24dB/0ct).

    Dev; :D:D:D
     
    cooky1257, Sep 30, 2009
    #42
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  3. cooky1257

    bottleneck talks a load of rubbish

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    Hi Cooky

    you know, every comp. driver Ive had in my house (vitavox (briefly) Altec, Tannoy now TAD begins to roll off about 14khz.. do you think it's indemic to the breed?

    I thought about the TAD berrilium supertweeters until I found out how much they cost and turned as purple as a goosebury !

    Using JBL 2405, which is a lovely tweeter, best for the money IMO, if not SOTA in comparison with multi thousand pound comp. tweeters.
     
    bottleneck, Sep 30, 2009
    #43
  4. cooky1257

    i_should_coco Monkey

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    Pretty much, yeah. Anything above that is down to resonance and will sound pretty shit.
     
    i_should_coco, Sep 30, 2009
    #44
  5. cooky1257

    cooky1257

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    Well the 435 Be was allegedly a breakthrough in getting a non resonance enhanced response out to 15khz but see this from JBL, the new S9900 http://www.audioheritage.org/vbulletin/showthread.php?p=252245

    If you look at the response the uhf is just a super tweeter, the new 4" 476Mg unit runs in parallel out past 20khz. This is the magnesium diaphragm version of the 476 the other is 476Be as used in the Everest DD66000.

    I liked the 2405 bat killer too!
     
    cooky1257, Sep 30, 2009
    #45
  6. cooky1257

    joel Shaman of Signals

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    Looking forward to seeing what happens when you add the UHF driver. Will you get the JBL dip?
    Anyway, compare what you've got with the reality circa 1980
    [​IMG]

    Or even an early exclusive / TAD, model 3401:
    [​IMG]

    I'd be happy just letting it roll off at the top. Of course adding UHF is fine, just as long as you can't hear it ;-)
     
    joel, Sep 30, 2009
    #46
  7. cooky1257

    cooky1257

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    Those curves remind me of Greg Timbers' comment re the design shortcomings of the legendary JBL 4350 monitor, it goes along the lines of ;" no one told the 4350 it shouldn't work and so it does anyway!"
    Lots of manufacturers mislead and use single octave smoothing in their published response curves-those look very honest to me and as far as I know those Tad exclusives and JBL's sound wonderful. Peaks are nasty, dips are harder to detect.

    The ideal is to run 2 way, my own lugs are only good up to 13.5-14k anyway. the dip will come as it is an on axis comb filtering effect down to the hf driver locations- off axis and so realistically in-room, it is inaudible/masked-but we shall see.
    cooky
     
    cooky1257, Oct 1, 2009
    #47
  8. cooky1257

    joel Shaman of Signals

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    The measurements were made by Japanese journal Musen to jikken (M&J Journal) in an excellent 1980 book "Future Monitor Speakers". Of course there really was No Future, but it was fun to dream.
    Here are some Altecs...
    [​IMG]

    Diatone (Mitsubishi) AS3002, essentially NHK's (Japan's BBC) monitor speaker from the late 1950s (!!!) until the early 1990s
    [​IMG]

    [​IMG]
    This speaker, unknown outside of Japan, is one of the finest tranducers ever made IMHO. Superb.
     
    Last edited by a moderator: Oct 1, 2009
    joel, Oct 1, 2009
    #48
  9. cooky1257

    cooky1257

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    Wow those Diatones do look nice-anymore info?.
    Keep this coming Joel, I'm a sucker for this stuff.
    Cooky
     
    cooky1257, Oct 1, 2009
    #49
  10. cooky1257

    cooky1257

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    cooky1257, Oct 11, 2009
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  11. cooky1257

    cooky1257

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    Just taken delivery of a shipment of Ferrofluid. Lots of different types available, the spec for the 2435's is type APG S38n made by FerroTec USA.
     
    cooky1257, Nov 10, 2009
    #51
  12. cooky1257

    cooky1257

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    http://www.truextent.com/ are now making aftermarket beryllium dias available to general public, they are starting with the 4"'s and will release other 3 and 2" replacements later this year.
     
    cooky1257, Mar 20, 2010
    #52
  13. cooky1257

    bottleneck talks a load of rubbish

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    Hi Cooky

    Do you know if Truextent make a berrillium diaphragm compatible with the TAD 400/1/2/3 ?

    If so, I would be interested to know how much these cost for potential future purchases (not now, by any means, but future)
     
    bottleneck, Mar 20, 2010
    #53
  14. cooky1257

    cooky1257

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    Hi Chris,
    The TAD's are vapour deposition Be the Truextent(who make the dias for jbl)are solid foil Be so I couldn't say-I'd email them and ask as the 4000 series is pretty much a 375/2440 with redesigned phase plug. The prices are $730 each for the 4" dias.More info here http://www.electrofusionproducts.com/display_page.asp?page_id=1
    Cooky
     
    Last edited by a moderator: Mar 20, 2010
    cooky1257, Mar 20, 2010
    #54
  15. cooky1257

    cooky1257

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    bottleneck talks a load of rubbish

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    thanks cooky.
    Do you know how much they are going for? Cant see any prices on the web.

    Cheers
    Chris
     
    bottleneck, Mar 21, 2010
    #56
  17. cooky1257

    cooky1257

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    Chris,
    $732 each from electrofusion products.
    Check out the Lansing thread, 4331b has run plots.
    Cooky
     
    cooky1257, Mar 21, 2010
    #57
  18. cooky1257

    bottleneck talks a load of rubbish

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    !!

    still cheaper than the originals.
     
    bottleneck, Mar 21, 2010
    #58
  19. cooky1257

    cooky1257

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    Last edited by a moderator: Aug 10, 2010
    cooky1257, Aug 10, 2010
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  20. cooky1257

    cooky1257

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    I've been researching a possible mod to my bass driver-basically convert a 2235 to a 2234 to reduce cone mass and increase the resonant frequency slightly and watching an amusing thread elsewhere about speakers that 'do 20hz'.
    My reservations and observations of the power and excursion limitation at VLF fell on deaf ears somewhat but as it related to my own design and the approach of Greg Timbers in rolling the bass of early to allow for room placement I uncovered these graphs that shocked even me-and I thought I had the extent of these VLF 'limitations' understood.

    Bear in mind this is professional drivers representing pretty much close to state of the art.

    Look at the max power input at vlf, in a high power driver it's down to only a few watts!
    The excursion is also a real eye opener.
    With this in mind and thanks to the convenience of DSP I'm now running with a steep lf filter below 30 hz.The benefits are clearly audible.
     
    Last edited by a moderator: Nov 4, 2012
    cooky1257, Aug 26, 2010
    #60
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