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Thread: Vibration Isolation Info

  1. #11
    Join Date: Apr 2008

    Location: Cheshire, UK

    Posts: 2,604
    I'm Clive.

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    I've found the idea that speakers need to be rigid coupled to prevent the loss of transients isn't the case at all. At least that's my experience with some hefty bass drivers. I have open frame (ie no baffle) 15 inch bass drivers. These cover 18Hz to 110Hz in my system. The drivers are wired in reverse polarity and face each other so the cones travel in the the same direction, not cancelling out forces.

    The interesting part is that the drivers are suspended by steel wires. The drivers are free to move - totally the opposite to normal practice. I was skeptical this could work as intuitively you'd think when bass kicks in the drivers will move and wreck the leading edge of notes. The reality is that this does not happen. I can perceive no physical movement of the spiders. Bear in mind that with all the bass cancellation involved with open frame there an enormous amount of power feeding these drivers...(900W per driver - yes I use 2 stereo class d amps to power these). Even on really bass heavy material such as Kraftwerk - The Man Machine - the only movement is from the cones - [U]massive[U] excursions. The bass is easily these the best I've had and pretty much the best I've heard.

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  2. #12
    Join Date: Mar 2017

    Location: Seaford UK

    Posts: 642
    I'm Dennis.

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    Your results are interesting Neil, and somehow I feel that we are fed ideas without verification by the market.

    My speakers weigh 77kg and are have an MDF base of 1.5" thickness. They are 20" front to back by 17", and are resting on new carpet (non foam) pile. What is your opinion on that arrangement? I have bought S/S domes to screw into the bases which were originally designed for spikes, but you can imagine 77kg on spikes into a wooden floor? I really wonder at the need for even the domes.

    That arrangement is interesting Clive, but arguably the main transient power is in the harmonics, this being felt when in phase with the fundamentals. Yours remind me of the Celestion 6000 woofers, but they were bipole and not dipole like yours. I remember the Hi-Fi News write up on the ideas behind the resulting smooth bass response.

  3. #13
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 44,883
    I'm Grant.

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    The movement should equal out at a guess. Interesting idea
    Regards,
    Grant ....

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  4. #14
    Join Date: Apr 2008

    Location: Warrington

    Posts: 2,932
    I'm Neil.

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    Quote Originally Posted by Pharos View Post
    Your results are interesting Neil, and somehow I feel that we are fed ideas without verification by the market.

    My speakers weigh 77kg and are have an MDF base of 1.5" thickness. They are 20" front to back by 17", and are resting on new carpet (non foam) pile. What is your opinion on that arrangement? I have bought S/S domes to screw into the bases which were originally designed for spikes, but you can imagine 77kg on spikes into a wooden floor? I really wonder at the need for even the domes.

    That arrangement is interesting Clive, but arguably the main transient power is in the harmonics, this being felt when in phase with the fundamentals. Yours remind me of the Celestion 6000 woofers, but they were bipole and not dipole like yours. I remember the Hi-Fi News write up on the ideas behind the resulting smooth bass response.
    Youíre right, those are some heavy-ass speakers, even with the most appropriate Sorbothane I could find, 4x spheres would support 40kg, so you would need 8x under each speaker... and even then what a ballache to site.

    From what I can see, perhaps the Auralex Gramma would be more appropriate, if at all...
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