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Thread: Jbl 2447 with aquapas dia?

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    Jbl 2447 with aquapas dia?

    As the title says, I have mint 2447 drivers and was reading about the aquaplas damped diaphragms, does anyone have any links to info or response graphs or first hand experience with the d16r2451 in a 2447 core? regards Greg

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    Here's a fellow who recently went to aquaplas coated diaphragms in a pair of 2446, so similar:

    http://www.audioheritage.org/vbullet...l=1#post399991

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    Thanks Jeff, i hadn't seen that thread. I have searched up lots of info on the aquaplas diagraphams but was hoping someone had first hand experience with the 2447 core and maybe even some comparative measurements. As I understand the aquaplas will be slightly more detailed less bright and more natural and slightly less sensitive. The thing im not sure about is if i will loose significant hf extension and require a uhf driver. mind you my hearing runs out at 15k now. Greg

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    The 2447 looks like a ferrite 2451 to me, I would take a wild guess and say the 2451 diaphragm should be OK in the 2447. I bet you could find some comparisons of the different diaphragms in a 2451 and use that as a starting point.

    http://www.audioheritage.org/vbullet...estions-please

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    Hi Greg,

    I've had 2447j with both titanium and -SL diaphragms and 2447 with -SL diaphragm sounds much better than with titanium ones. I also have 2450SL and in its turn it sounds (not so much) better than 2447 with -SL diaphragm.

    No response graphs only listening impressions sorry.

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    Hi Alexander, thanks for the reply, if i may ask did you notice any difference in the hf extension between the ti and aquaplas diaphragms. regards Greg

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    Quote Originally Posted by greg32 View Post
    Hi Alexander, thanks for the reply, if i may ask did you notice any difference in the hf extension between the ti and aquaplas diaphragms. regards Greg
    Hi Greg,

    What kind of horn You would to apply with 2447 driver?
    The influence of the horn can not be neglected.
    Regards
    Ivica

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    Hi ivica, I am using the 2381 at the moment from 1200hz Greg

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    I have just ordered a pair of d16r2451sl diaphragms. for the record i will measure and post the response graphs for the std ti and sl diaphragms in the 2447 cores. Greg

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    Senior Member ivica's Avatar
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    Quote Originally Posted by greg32 View Post
    Hi ivica, I am using the 2381 at the moment from 1200hz Greg
    Hi Greg,
    Nice to show us off-axis response too, with the 2381 horn and 2447 core.
    Good luck!

    Just some of my experience with SL diaphragms
    http://www.audioheritage.org/vbullet...highlight=2332

    http://www.audioheritage.org/vbullet...PT-F95HF/page2


    Ivica

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    Ivica a pleasure to do so. i have not measured off axis before but can make a protractor and measure.
    what are the standards for off axis? 10deg? 20deg? etc
    Greg

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    Quote Originally Posted by greg32 View Post
    Ivica a pleasure to do so. i have not measured off axis before but can make a protractor and measure.
    what are the standards for off axis? 10deg? 20deg? etc
    Greg
    Hi Greg,
    I think only horizontal 15, 30 and 45 degs offaxis would be enough, and I would suggest to EQ 15 deg. Off-axis response....as a reference.

    Regards
    Ivica

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    Quote Originally Posted by greg32 View Post
    Hi Alexander, thanks for the reply, if i may ask did you notice any difference in the hf extension between the ti and aquaplas diaphragms. regards Greg
    Greg, HF extension has the biggest difference: Ti diaphragm sounds obviously harsh.

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    Hey, Greg, curious if you've successully swapped your 2447 - SL diaphragms yet? I have to do the same thing and was wondering if there were any tricks involved or any special precautions.

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    Quote Originally Posted by emilime75 View Post
    Hey, Greg, curious if you've successully swapped your 2447 - SL diaphragms yet? I have to do the same thing and was wondering if there were any tricks involved or any special precautions.

    No need to observe much if your cores are marked close to "0" after opening the back lid. If you see a felt pen marking like +3 or -3, you would need to take care that your diaphragms have a simlar value written into the inside of the coil former. The markings on the magnet pole plate describe the "height" of the phase plug over the mounting plane of the dome ass'y.

    If the deviation from design standard (= "0") was high, JBL took care to put frams in that deviated from standard correspondingly.
    Sounds almost as unlikely as the story about the lady with the ball pen correcting 075 fram suspensions. Craft is art sometimes.

    Ralph

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