My projector mount is attached to wood work/the trusses by four screws. However any time someone walkes through the kitchen above on the main floor, I get a vibration that shakes the picture a little. Any thoughts on how to fix this?
This isn't a picture of precisely what I was describing since your ceiling is drywalled already. So imagine the ceiling is drywalled. Then apply the clips and channels. 4 clips, 2 channels.
Then attach a piece of MDF or plywood. You could router the edges up pretty. Attach the panel to the channel. The panel will move up and down like a shock absorber. This should help. At least it's an easy trial.
Often what causes movement in the floor is that there is not enough bracing between the beams. By placing some 2x6 pieces across the gap in the area where the projector is mounted for about 4' around you will stiffen up the floor and it should not move nearly as much.
It's probably screwed into the joist though I bet. What you could try is putting a neoprene or soft rubber washer between the ceiling and the mount where the screws go though the ceiling.
If there is still a some movement a home made vibration damper could be made by adding a bracket with neoprene or soft rubber in between the mount and the ceiling. The projector mount screwed into the bracket and then the bracket into the ceiling. That way the screws that secure the mount don't transfer vibrations from the joists/ceiling. With that description you probably get the idea and could come up with a plan of your own.
If there is a lot of vibration then more damping is needed. One thing to consider too is that excess vibration transferred into the projector can also damage the bulb and could make it fail prematurely.
Sometimes it is wise to 'sister' the joists and add cross bracing in the area where the projector is going to be mounted as the room is being constructed. This will stiffen the floor/ceiling assembly and reduce the vibration from a structural standpoint.
The trouble with trying to mount the projector with vibration damping mounts is that they are so light. There are very few materials that will function properly on those light loads. You could in fact make it worse as you could increase the amplitude of the vibration with the wrong pad.
Not thinking sistering or otherwise stiffening will affect change in the small zone around the projector. The rest of the floor system will still be oscillating even though the small area around the projector is stiffened.
A resilient mount will have a better chance to separate the projector from the ceiling.
I should have been clearer. Ted you are right you can't do just a small area it would have to be sistered back to 'room edge support point' to be effective.
I love isolators and use them all the time but using the wrong one could leave you in a worst off condition actually increasing the amplitude. Perhaps as you have suggested using 4 mounts on two pieces of furring channel with a broad base of double layered plywood, Green Glue between the layers for damping. Screw the plywood assembly to the furring channel and the projector to the plywood base. Paint it to match the room. Does any company make a kit for this?
Projectors are mounted on ceilings decoupled with clips as a common practice. But the resulting spring has a low resonance due in part to the mass of double drywall hanging on it. To your point, Bill, a heavier panel attached to this little clip assembly would ensure a low frequency resonance.
I think it would do a fine job. The only challenge would be to make it look nice enough to get the "wife approval". The clip and furring channel would keep the dampened wood 'base' off the ceiling by approx. 1-5/8" so if you put edge return molding on this to go back to within say 3/8" of the ceiling, leaving a reveal, it would look like it was cabinet work put in place to mount the projector.
I'd want to be doing it while I was using Green Glue for something else. I would not want to waste a whole tube.
Question: Is this just an annoyance as someone walks over making the projector shake or can it actually damage some/all projects over time?