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Discussion Starter · #1 ·

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Remind me again how your ceiling is built.
 

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Triple leafed? I'm having a hard time picturing the layers.
 

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Sounds like a trip-leaf to me, too, though that soundboard is somewhat low mass.


For the larger reading audience, if the ceiling is decoupled (clips & channel) this is rarely an issue.


Wooly, you might consider building a decoupled platform as well.
 

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I had this issue and got a couple of things called subdudes, one for each sub. The subs seem to sound a little better perhaps and it stopped the dual 15" powered subs from shaking the projector. So if your subs are not built in, give em a shot.
 

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Can someone explain how isolation of a sub helps? Are the sub cabinets themselves really vibrating so wildly that they actually impart enough vibration into a structure to move the projector?


I would think that any vibration would be 99.8% airborne, with 0.2% impact
 

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Discussion Starter · #9 ·
I believe my vibration is all airborne but I'll try anything that mite work. A friend of mine has one of those sub isolation pads I will have to have him bring it by and see if it will make any difference. I'll try anything that mite work.
 

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Think about that decoupled PJ platform I mentioned. Simple enough to build and try
 

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Quote:
Originally Posted by W00lly /forum/post/18294910


Ted


Not sure I want to tear into what I already have done
Unless I could build another piece of oak below that with the isolation pads in between.

Man that looks nice...


I was sugesting building this platform on top of what is there now
 

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Clips don't work without the channel, but yes, something like that
 

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If you're not careful you'll end up building something that will be more prone to resonance than your current mounting solution. What is the current motion? Does it rock on your mount around the center of attachment, or is the whole thing going up and down vertically?


Have you nailed down what frequency causes your problems yet?
 

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Personally, I would try a plate bolted to the ceiling and sandwich a few rubber washers between and see if that helps. Cheaper than those solutions that you linked above and if it works great, if not you're out a couple bucks.




My .02 cents
 

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Discussion Starter · #17 ·
That was the reason for the post as I looked for reviews of the mounts above but could not find any. Maybe I should be the first to try one of them out as money is not an issue
 

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Quote:
Originally Posted by Spec4 /forum/post/18295351


Personally, I would try a plate bolted to the ceiling and sandwich a few rubber washers between and see if that helps. Cheaper than those solutions that you linked above and if it works great, if not you're out a couple bucks.

I'm not so sure about that. I'm not a mechanical engineer but depending on how his projector is moving making its mount less stiff by introducing flexible components may only worsen his problem. For example if it swings forward and back on a small scale like a pendulum while the ceiling is stationary he needs a stiffer mounting arrangement, not a more flexible one (or more mass to lower it's resonant frequency). If his ceiling is moving up and down vertically moving the projector with it he needs to suspend the projector somewhat like a tuned mass damper so the ceiling will move while the projector remains stationary via inertia (which may also require adding mass to the suspended projector).
 

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To Stereodude's point, generally you introduce a spring isolation system that has a resonance point below the offending frequency. That would be one big item. Not practical, perhaps.


So testing a couple of resilient alternatives would be quick, easy and cheap.
 

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I would assume the rigid mount that's there now would prohibit forward and back motion. That may be a poor assumption.


To continue with my assumptions, I'd wager that the motion is up and down, and at its worst when you're playing back that ceiling's natural resonance frequency.


I am more inclined to support my original concept, and test different weight loads. Might help, or simply shift the problem to another frequency
 
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