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Thread: Differences between compression drivers

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    Administrator Robh3606's Avatar
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    Differences between compression drivers

    This is to continue a conversation about compression driver design and the effects material, surround type and geometry have on the HF time domain of the secondary resonance of the drivers.

    Typically 10-20Khz.

    Take a look at the attached video talking about material differences, surround differences and the effects. It's informative and we can discuss in the thread.

    Rob

    https://www.youtube.com/watch?v=x9NAVlwvLro
    "I could be arguing in my spare time"

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    Hey Rob,

    This has video does a good job of expanding all the various aspects of diaphragm materials and behaviours.

    The 18 Sound presenter at the end has offered the pdfs of the video. Why not see if you can post them for awareness and educational purposes.

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    Administrator Robh3606's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    Hey Rob,

    This has video does a good job of expanding all the various aspects of diaphragm materials and behaviours.

    The 18 Sound presenter at the end has offered the pdfs of the video. Why not see if you can post them for awareness and educational purposes.
    God idea see if I can find them.

    Rob
    "I could be arguing in my spare time"

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    I have contact details of a Tech Lead at B & C so leave it with me.

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    With the exception of bizarre behavior like licking Beryllium diaphragms, that's a great video. Frequency response alone doesn't tell all you need to know.

    Loved the anecdote of the pro audio guys who wanted to return to using the drivers with the Godawful ringing because they preferred the 'sizzle'. :-D

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by rusty jefferson View Post
    With the exception of bizarre behavior like licking Beryllium diaphragms, that's a great video. Frequency response alone doesn't tell all you need to know.

    Loved the anecdote of the pro audio guys who wanted to return to using the drivers with the Godawful ringing because they preferred the 'sizzle'. :-D
    Damn... licking Be, now I must find the time to watch the video!


    Widget

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    Senior Member DerekTheGreat's Avatar
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    Better make yourself comfortable, the damn thing goes on for over an hour. I gave up trying to find the Be licking and the "sizzle" comment

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    Administrator Robh3606's Avatar
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    Quote Originally Posted by DerekTheGreat View Post
    Better make yourself comfortable, the damn thing goes on for over an hour. I gave up trying to find the Be licking and the "sizzle" comment
    1:18

    What surprises me is how clean the JBL Ti SL and Magnesium drivers are compared to many of the driver CSD's in the presentation.


    Rob
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    Senior Member DerekTheGreat's Avatar
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    Quote Originally Posted by Robh3606 View Post
    1:18

    What surprises me is how clean the JBL Ti SL and Magnesium drivers are compared to many of the driver CSD's in the presentation.


    Rob
    Thanks Rob! That was funny, the one guy goes, "Don't--" to which the Be licker guy goes, "Nah nah, that's if you grind it up into dust and snort it. Which this is rock & roll, so somebody might.. Don't do that." haha

    ...Matteo said they're going to release a 15" Coax driver??? Any details on this?

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    Administrator Robh3606's Avatar
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    Just a reference here a CSD plot of an equalized 476 Mg. It's very clean and doesn't show as much stored energy say compared to the 2453 SL CSD. That said the 2453 is also very clean.

    Rob
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    Quote Originally Posted by Robh3606 View Post
    Just a reference here a CSD plot of an equalized 476 Mg. It's very clean and doesn't show as much stored energy say compared to the 2453 SL CSD. That said the 2453 is also very clean.

    Rob
    That's super clean and way nicer than the 3" MG diaphragm they showed in that video. Is that the mid driver in the 1400?

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    Administrator Robh3606's Avatar
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    Quote Originally Posted by rusty jefferson View Post
    That's super clean and way nicer than the 3" MG diaphragm they showed in that video. Is that the mid driver in the 1400?
    Hello

    That's on an M2 waveguide, it's a 4" Compression driver used in 9900, 4365 and a lower cost version of Everest.

    Rob
    "I could be arguing in my spare time"

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    Quote Originally Posted by Robh3606 View Post
    Hello

    That's on an M2 waveguide, it's a 4" Compression driver used in 9900, 4365 and a lower cost version of Everest.

    Rob
    It's a 4" compression driver that JBL used to use in the 9900, 4365, and lower cost DD65000 Everests. Now JBL is using a Radian built 4" compression driver with presumably the same diaphragm. That is assuming anyone is still buying the K2-S9900 or the DD65000s are even still being offered.

    Unfortunately the rather excellent JBL 476Be and 476Mg drivers are NLA and just a couple of additional legacy pieces of excellent engineering and manufacturing.


    Widget

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    Quote Originally Posted by Mr. Widget View Post
    Damn... licking Be, now I must find the time to watch the video!


    Widget
    Licking Be, I'll bet it tastes like chicken.

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    Quote Originally Posted by jpw retired View Post
    Licking Be, I'll bet it tastes like chicken.
    You know the big step up in JBL compression drivers used to be the 375 not only physically but in price.

    On a lighter note l am wondering if we should come up with a Tech sheet that says use only the Radian aluminium- magnesium- copper alloy diaphragms in these monsters. ( a proprietary hardened alloy).

    If you’re under 50 chop them with a steep slope @ 10,000 hertz and add the tweeter of your choice. (Radian have some excellent planar ribbon which Vance Dickason comments are worthy of studio monitors)

    The vertical polar is lousy but let’s not go there.

    https://audioxpress.com/article/test...io-engineering

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