And let's get this out of the way... I don't mean rub it or play X-Rated movies

Since I've had the EP800s, I've noticed that my projector shakes a lot during LFE effects, and it is very distracting. I have a Panasonic PT-AE3000U projector and one of those ceiling mounts that is center oriented with 4 connections to the projector. I was thinking of possiblly adding rods to the 4 corners of the projector, tight against the ceiling. It's kind of weird because the speakers are sitting on the concrete foundation of the house, and the projector mount is bolted to a structural beam, so the only way it is shaking is from the air pressure, not from vibrations transferred through the floor.

Any help would be greatly appreciated!

Mark should be along soon with ideas on how to get bass to cancel for your screen using square roots... square rooms...

What kind of mount do you have? Is it two seperate pieces, one that bolts to the projector and another to the ceiling, and you lock them together? I have that style and I have no issues at all.

Maybe try some blue loc-tite on all the bolts on the mount (not the ones into the projector!!) and see if that helps at all, although it may not if the mount bolts are not actually coming loose.

It is 2 separate pieces, but it is pretty tight. After many hours watching, even with the vibration, the projector is still aimed perfectly at the screen. If it were loose, I think it may have eventually slipped a bit. I had the same style when I had my Panasonic PT-AE900U and my EP500s and there was never an issue, but the PT-AE-3000U is quite a bit bigger (side to side) and the new subs put out more bass.

For the record, I don't own or know much about projectors...BUT!!...would it not be prudent to isolate the projector somehow with something like rubber pads/grommets/gasket kind of the way you might do to your speakers sitting on the floor. I realize this is caused by air pressure, but it still might help as well as firming up the supporting structure. Could it be the sound pressure acting on the floor beams....then to the projector?...maybe some pads might help to isolate it.

If your projector mount is rated for more weight than it's currently holding, I would try adding weight to deaden the vibrations. You can test out the theory by securing a heavy book or two to the mount with bungie cords or cam straps. You'll get more dampening if you hang the weight beneath the projector, but it might not be feasible.

I would suggest Floyd Toole's "Sound Reproduction" to start with.

If your projector is attached to the ceiling joists there is not a lot you can do in my opinion. I have a DIY mount using cast iron steel attached across the ceiling floor joists in my basement. I get the occasional shaking from my subs, as well as when the kids are jumping upstairs. Provides a realism to action movies.

I think your best bet is to isolate the mount from the ceiling and bolts. Put neoprene (sp?) between ceiling and any contact points, and put thick soft gaskets or neop on floor side of the anchor bolts.

50/50 chance it gets better. But anchoring it more tightly I thinks is a hard road, unless it is really loose right now. With that much SPL, you won't get all the shake out of the structure, so you have to isolate.

I would say the weight idea also.. I would make a mold of the top of the projector, and get some led, and melt it so that I would have a good fit with some double sided tape.

the bolt idea that Zimm said, will most likely not work due to the bolt going though the stud, and then to the projector, so the bolt will still be a sound or vibration short.

you would need to do something similar to a motor mount, with 2 studs that go into a common rubber mount, but the 2 studs are not physically touching. something like this.

http://www.rubber-group.com/isolationmounts.html

Yeah, by increasing the mass at the end of your projector mount, you are increasing the system's moment of intertia, which increases its resistance to changes in motion.

Have you taken the time to note what kind of vibrations you're getting? If they're perpendicular to the pole, this method should result in a great improvement.

I got back home last night, so I'll definitely take a closer look at some of these suggestions and how exactly my projector is vibrating. The replacement EP800 and new amp for sub #2 is here, so I could temporarily hook 3 EP800's up to really see if I can make it shake!

Dude, three 800s would make MY projector shake here in NH...

...if I opened my Indiana-facing window a bit...

...and if I had a projector....

...and my room didn't null it out....

Now showing in The Nullifier Chamber (a.k.a. Mark's living room): U-571

Mark will personally kick the sofa during the depth charge scenes to simulate bass.

Now that's funny raht thar! A true LOL moment.

Mark told me he actually prefers to recreate the extended bass notes via flatulence.

Mark's wife: "Honey, that's your fourth can of chili this morning! Are you okay?"

Mark: "I'm fine. Just planning on watching the Lord of the Rings trilogy today."

LMAO!!!

You guys wait for the Axiom get together...especially during the subwoofer shootout.

I'll get my revenge then. Oh yeah. I said shootout.

It's really easy to post something diabolical while I have a Stewie avatar, BTW.

Did he ever finally watch Band of Brothers? I'm asking you even though he's right here.

Mark has not.

He keeps promising, but. . . .

I watched the first two episodes, but haven't gotten back to it.

I had the same problem. I ended up getting some rubber / neoprene type weather stripping for exterior doors. The kind with an adhesive backing that you just peal off. I stuck that to the mounting plate, then snugged it up to the ceiling. It helped some, but not completely. I’m going to try some thicker stuff the next time in a hardware store with a larger selection.