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

  1. #121
    Senior Member jackgiff's Avatar
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    2235's and 2431's

    I had a hard time finding 2235's, so bought a pair of 2225's and had Orange County Speaker recone them as 2235's. The 2431's seemed to be the best bet, so that is what I used. Zilch was a real blessing to my project, but tested so many drivers, I got confused about which ones to use. I am a happy camper now though. In fact, they have replaced my original factory purchased 846A Valencias in my office, but were really meant to be in our new home when it is done.

    Yes, that is rosewood. Didn't finish as nice as the 4412's, but still looks OK.
    Last edited by jackgiff; 09-12-2005 at 03:36 PM. Reason: additional text

  2. #122
    RIP 2011 Zilch's Avatar
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    H3100 throats came in.

    Here --- havva seat....

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  3. #123
    RIP 2011 Zilch's Avatar
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    H3100 Throat Details:

    1) H3100 driver mount.

    2) H3100 throat compound transition incorporates a broad constriction including the familiar racetrack oval.

    3) - 5) Three views of the interior of the cast aluminum throat. Note finish quality....
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  4. #124
    RIP 2011 Zilch's Avatar
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    H3100 Throat Details Continued:

    6) Half of throat mounted to horn.

    7) LE85 completes horn assembly. Exterior of throat looks likes it's smashed on the side, but that's where the final transition to rectangular occurs. Even that is curved....
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  5. #125
    RIP 2011 Zilch's Avatar
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    Performance:

    1) Impedance of LE85 on H3100.

    2) Impedance of 2426J on H3100. Error in title (2226J) is too hard to fix.

    3) RTA LE85 with 3110A crossover, mid = min, HF boost = max (not enough) per stock 4660.

    4) RTA 2426J, same conditions.

    5) Citation 7.4/H3100 in Everest orientation.

    These horns do not exhibit phase or response anomalies found with 2346. I'll verify this by retesting the Everest horns.

    What's this have to do with 4430?

    It's a Biradial two-way with a decidedly different dispersion characteristic, is all. Closer than I might ever have imagined.

    [Crossover work needed.... ]
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  6. #126
    Senior Member B&KMan's Avatar
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    Quote Originally Posted by Zilch
    1) Impedance of LE85 on H3100.

    2) Impedance of 2426J on H3100. Error in title (2226J) is too hard to fix.

    3) RTA LE85 with 3110A crossover, mid = min, HF boost = max (not enough) per stock 4660.

    4) RTA 2426J, same conditions.

    5) Citation 7.4/H3100 in Everest orientation.

    These horns do not exhibit phase or response anomalies found with 2346. I'll verify this by retesting the Everest horns.

    What's this have to do with 4430?

    It's a Biradial two-way with a decidedly different dispersion characteristic, is all. Closer than I might ever have imagined.

    [Crossover work needed.... ]

    Hi Zilch,

    Again beautiful works and juicy stuff....

    euh question for you.

    the slope response on 2426J it is due to electrical impedance mismatch.

    the Le85 is a really beautiful response but the impedance is increased by 2 if you compare with 2426J .

    It is possible to explain his phenomenon ???

    Jean

  7. #127
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by B&KMan
    It is possible to explain his phenomenon ???
    Hi, Jean.

    There's a difference of 40 years in the diaphragms, and different driver designs, of course. Also, LE85 is aluminum with tangential surround, probably, whereas, 2426J is brand new diamond surround titanium.

    I'd be reluctant to conclude anything unless I ran several of each type. This becomes a statistical exercise when dealing with drivers having indefinite histories.

    Four additional points to consider:

    1) Crossovers (like 3110A) with tapped inductors are less sensitive to HF driver impedance variations; I doubt it's impedance alone,

    2) The 2426J response curve seems flatter, actually. It needs different HF boost (though both might benefit from more),

    3) If I backed off the HF boost on the LE85 a bit, the two driver response curves might be more closely matched, and,

    4) I forget the last point, now....

    Edit: Oh, yeah, I remember now. Note that the impedance scales are different on the two plots.

  8. #128
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    Hi Zilch

    1) Crossovers (like 3110A) with tapped inductors are less sensitive to HF driver impedance variations; I doubt it's impedance alone,
    - I remember seeing and reading Giskards info that created this above reference. Do you know where that post is located ? I'd love to reread it .

    - Any chance of retrofitting those H3100/le85 horn combos into old L200s ?

    Thanks

  9. #129
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Earl K
    I remember seeing and reading Giskards info that created this above reference. Do you know where that post is located ? I'd love to reread it.
    Actually, my statement derives from a recent empirical determination in which I came out looking stupid for not knowing that. We pursued it relentlessly here:

    http://audioheritage.org/vbulletin/s...9&page=1&pp=15

    I'd like to read the Giskard reference as well, if somebody can find it.

    There's the throat details you asked for, above. I'm certainly glad I persisted to obtain them. JBL put considerable effort into that design.

    No way could I have replicated those in plywood. It'd take some SERIOUS negotiation with Mr. Widget's CNC setup to accomplish that.

    Quote Originally Posted by Earl K
    Any chance of retrofitting those H3100/le85 horn combos into old L200s?
    Lemme make some quick measurements here....

    Edit: No, alas, not without a new baffle. 2344A would JUST squeeze in there above the woofer. H3100 is 1" taller....

  10. #130
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    I'd like to read the reference as well, if somebody can find it.
    - Then I'll see how the weekend goes for time before looking around .

    Edit: No, alas, not without a new baffle. 2344A would JUST squeeze in there above the woofer. H3100 is 1" taller....
    - Oh well .



    EDIT :
    There's the throat details you asked for, above. I'm certainly glad I persisted to obtain them. JBL put considerable effort into that design.
    - Those look to be well made castings. I like the sexed halves.. ( Must be French ! ) They "look" heavier than any of the previous pictures suggested .

    - I assume those horizontal "sides" of the throat are of a slightly different length when forming the ??? entry angle .

  11. #131
    Administrator Robh3606's Avatar
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    Is this what you are looking for??

    http://www.audioheritage.org/vbullet...apped+Inductor

    Rob

  12. #132
    Administrator Mr. Widget's Avatar
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    Rob,

    I knew there was a reason we kept you around.
    That Giskard was a useful fellow too.


    Widget

  13. #133
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Earl K
    - I assume those horizontal "sides" of the throat are of a slightly different length when forming the ??? entry angle .
    Nope, they're isosceles triangles, with the mouth being slightly wider. The 30° angle is established by the horn.

    See the top pic at post #571, above....

  14. #134
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    Nope, they're isosceles triangles, with the mouth being slightly wider. The 30° angle is established by the horn.
    - Okay, Thanks !

    - Say Zilch , have you tried taking advantage of that seemingly "extra" 3 db HF boost ( between 10 & 20K / from the 10 db pad tap ) that's naturally builtin into those "electrically wonky" autoTransformers ? ( Wait; it's a feature, no it's a design flaw, no, feature !, flaw ! , whatever ,,,,,)



  15. #135
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Earl K
    Say Zilch , have you tried taking advantage of that seemingly "extra" 3 db HF boost ( between 10 & 20K ) that's naturally builtin into those "electrically wonky" autoTransformers ? ( Wait; it's a feature, no it's a design flaw, no, feature !, flaw ! , whatever ,,,,,)
    Yeah, it ain't enough to do the job, tho.

    As Giskard suggested in the reference Rob cited above, there's easier ways to accomplish what's required.

    [I'll discover them one day.... ]

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