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Thread: Lynn Olson's comment on aquaplassed diaphragms

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    Senior Member pos's Avatar
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    Lynn Olson's comment on aquaplassed diaphragms

    I found this interesting comment from Lynn Olson on the diyaudio.com forum about the aquaplassing of compression drivers diaphragms:

    One of the things I'll be mentioning to Great Plains Audio is applying Aquaplas (now called Antivibe) to the tangential surround of the aluminum compression driver diaphragm. JBL applies Aquaplas/Antivibe to the whole diaphragm when you buy a 435Be, but I feel this is a mistake. The part of the diaphragm with the most chaotic radiation is obviously the surround, and it's an area where mass-damping and outright suppression of radiation is desirable. That is NOT true of the diaphragm dome, where low-as-possible mass and uniform emission into the phase plug assembly are primary goals. Raising the mass of the diaphragm is extremely undesirable, since it depresses efficiency and decreases HF extension.

    Since the dome of the diaphragm and its surround operate in completely different ways, and in fact have completely different functions, it only makes sense to treat them differently, rather than applying damping goo to the whole thing. Adding a bit of mass damping to the surround seems like a good idea, and is likely to improve the mechanical termination between the moving diaphragm and stationary mounting ring.
    http://www.diyaudio.com/forums/showt...26#post1552226

    Has anyone here tried to aquaplass only the surround of a diaphragm?

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    Senior Member GordonW's Avatar
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    Quote Originally Posted by pos View Post
    I found this interesting comment from Lynn Olson on the diyaudio.com forum about the aquaplassing of compression drivers diaphragms:


    http://www.diyaudio.com/forums/showt...26#post1552226

    Has anyone here tried to aquaplass only the surround of a diaphragm?
    This sounds similar to the rationale that Renkus used, when creating the Symbiotik diaphragms for Altec. A different material combination for the surround, to damp vibrations...

    However, as that project proved, this idea is sometimes harder to do, than to talk about. IME, Radian finally "got it right", with their implementation of that idea... so, it can definitely work...

    Regards,
    Gordon.

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    Everyone is entitled to his opinion, however, we have hard measurements in addition to much subjective listening that shows that the application of Aquaplas to the metal diaphragm of our compression drivers improves the sound. There is a slight additional HF roll off which is introduced but we can normally equalize it out in the network. Even the Beryllium diaphragm improves. The effect is in the time domain and does not show up in simple response and harmonic distortion measurements. We have seen up to a 10 dB reduction in hash on ETC measurements. The sonic effect is an increase in detail and smoothness coupled with a reduction in harshness.

    Applying the treatment to the surround can often help also. Unfortunately, the sensitivity loss can be greater due to the large area of the surround. The hash reduction is not realized when the surround is treated, although sometimes there is a small response improvement.

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    Administrator Robh3606's Avatar
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    Thanks Greg for responding and setting the record straight. I like what Aquaplas has done for my drivers.

    Rob

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    Senior Member spkrman57's Avatar
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    All or nothing....

    If you go to the trouble of having diaphrams "aquaplas'd" I would think it would not be worthwhile to only treat the surround.

    As GT mentioned, JBL did extensive testing and treating the entire diaphram is a definite improvement.

    Regards, Ron

    PS: Thanks to GT for providing his input. Many of us here hold his wisdom in high regard!
    JBL Pro for home use!

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    Senior Member Hoerninger's Avatar
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    My thank goes to Mr.Timbers as well.
    And a delightful demonstration of the EVII showd me "no flaws".
    ____________
    Peter

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    Thanks for the post Greg!

    Quote Originally Posted by spkrman57 View Post
    PS: Thanks to GT for providing his input. Many of us here hold his wisdom in high regard!
    Yep, he has certainly provided alot of us with many years of mighty fine transducer, filter and system designs.

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    Does this Aquaplas'd improvement only apply to the Be and Ti dias or does it work on the aluminium 2441 dias too?
    Cooky

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    Quote Originally Posted by cooky1257 View Post
    does it work on the aluminium 2441 dias too?
    Yes.

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    Quote Originally Posted by 4313B View Post
    Yes.
    Thank you.
    Anyone know a man that can.....?

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    Senior Member GordonW's Avatar
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    Quote Originally Posted by Valentin View Post
    some one should post this explication for mr lynn to read in diyaudio
    I would wonder if Lynn Olsen is already familiar with the conclusions Greg Timbers noted from the JBL research, or not.

    If not, then yes, it might be useful, in promoting discussion, to present it to him.

    If so, then it may be an example of possibly "agreeing to disagree", or something of that sort... I've seen very talented speaker designers (sometimes all capable of fantastic products in their own rights) go seemingly diametrically opposed directions before... it can be bewildering sometimes. :dont-know


    Regards,
    Gordon.

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    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by Valentin View Post
    some one should post this explication for mr lynn to read in diyaudio
    or he could listen to a 2450SL or whatever

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    Administrator Robh3606's Avatar
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    or he could listen to a 2450SL or whatever
    Thank you! If he listened to a pair of coated drivers OK fine. To just apply textbook physics to say it was done wrong?? Come on. Talk about the tail wagging the dog, at least give it a listen.


    Rob

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    Senior Member Ian Mackenzie's Avatar
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    I really would not pay too much attention to what Lynn thinks and says.

    He has after all by his own admission been outlawed by the audio industry for some of the things he has said and done over the years.

  15. #15
    Senior Member Guido's Avatar
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    I install aquaplassed dias in almost every speaker I build or upgrade. Not one of the people that own the speakers now wasn't completely satisfied with the sound.
    So, who cares .......

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