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SVS plus destroyed my Image Quality


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6 replies to this topic

#1 of 7 OFFLINE   Ian_J

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Posted June 29 2004 - 02:41 AM

I’m pretty sure I screwed the pooch on this one but I wanted to fish for some recommendations anyway. Ok, here it is….

My dedicated HT is basically a room within a room. It has staggered stud walls on concrete floor with the ceiling of the theater suspended below the floor above (does that make sense?). Maybe this will help: The ceiling of the theater rests on top of the left and right soffits (2x6s 24” on center). This design basically isolates bass to the theater (goal achieved). However, in the process of isolating bass, I created a monster. My SVS plus vibrates the entire room. Sounds cool right? Wrong! During heavy bass scenes, like the beginning of Master & Commander, my front projector vibrates to the point that it shakes the image and eventually causes the picture to become misaligned with my screen.

20/20 hindsight tells me that I should have connected the projector to the floor above instead of only to the ceiling of the theater. At this point, I’m not willing to cut a 2’ x 2’ hole in my new ceiling to fix the problem. I’ve considered isolating the top plate of the projector mount with an isolation pad (compressed vinyl or something similar).

I’m very open to any other suggestions.

Thanks,
Ian

#2 of 7 OFFLINE   Dave Simpson

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Posted June 29 2004 - 05:32 AM

This might tame the beast. Works for me. Cheers.

DS.

"Buncha slack-jawed faggots around here! This stuff'll make ya a goddam sexual tyrannasorse...just like me!"

-The former Gov. Ventura

See It...In StrotoVision!!

#3 of 7 OFFLINE   chuckg

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Posted June 29 2004 - 08:20 AM

Sounds to me like an isolation pad for the sub won't do much. You've already got a concrete floor, which isn't known for transmitting a whole lot of vibration. It may just be that the sound in the air is "pumping" the walls and ceilings.

You could try a few layers of carpet under your sub, and see if it makes a difference. If it works, by all means get a fancy isolation pad - it will work better.

If that doesn't work, you may have to mount the projector to something other than your "internal" ceiling. You might try hanging the projector from a temporary stand of some sort to see if that cures the wiggles.

If removing the projector from the ceiling does work, but you'd rather not carve holes in the ceiling, can you put in a beam all the way across the room, suspended from the "outer room" walls? Might be too ugly, or may pose a risk to your noggin.

Can you very carefully "find" the floor joists above your false ceiling? It may be possible to screw a very long bolt or screw into those studs, and then attach something from them to hang the projector from. In my minds eye, I am thinking of "closet screws" which are actually for mounting a toilent. They have bolt threads on one end, screw threads on the other. You could screw the screw end into a joist, and then use the bolt end hanging down to attach threaded rod with couplers, or some such.

There are also fancy little metal thingys for hanging drop-celings. They have a screw thread on one end. The other end is flattened, and has a hole for a wire. You could get tricky and make that into a bracket for a projector mount.

Whatever pierces your false ceiling, leave a little gap around it so that the false ceiling can move around without transferring that to the projector mount.

Does that help any?
--ignore the man behind the curtain

#4 of 7 OFFLINE   Ian_J

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Posted June 29 2004 - 08:32 AM

I agree that isolating the sub won't help much. The pressure from the sub is moving the entire room (walls and ceilings) very little pressure is transmitted via the concrete. I like the idea of running bolts to the floor above but this will be a big job. All of the ideas ar very helpful so far. Any additional ideas are welcome.

Thanks a bunch!

Ian

#5 of 7 OFFLINE   Parker Clack

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Posted June 29 2004 - 09:04 AM

Ian:

I would give Tom or Ron an email about this. I am sure that they have run into similar situations and they should be able to give you some good suggestions.

I like your idea of an isolation pad or separate pads under the projector mount itself. It should keep the vibrations from the ceiling getting transferred to the projector. Kind of like putting isolations pads under a turntable to keep it from being affected when playing music loud.

Parker

"I tried to get my medical records from the company but they say they

are confidential and can only be released to other insurance companies,

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#6 of 7 OFFLINE   Ian_J

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Posted June 29 2004 - 09:17 AM

Thanks Parker. The isolation pads between the projector and the ceiling seem to be the easiest and cheapest option. I'll definately start with that before ripping open the ceiling.

By the way, I don't want anyone to think this problem was created by the SVS sub. It is clearly a design flaw on my part. I'm not even running the SVS hot and it'll still chase you right out of the room and kick you in the butt if you're not paying attention. As if it hasn't been said enough, SVS makes one heck of a quality product!

#7 of 7 OFFLINE   JackieDub

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Posted June 30 2004 - 01:15 AM

We had that problem in a conf room caused by the air conditioner.
We were able to wedge a piece of cardboard between the mounts and the vibration stopped.