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bass shaking projector

post #1 of 20
Thread Starter 
what are you guys with really big subs using to keep your projector from shaking from the big base sceens in movies. I have my projector mounted on my ceiling and it only happens in every once in awhile but that is enough to bother me. It happened in the beginning of Transformers with the helicoptor . I am using a SVS pb12 nsd/2. It will shake the walls, floor and sometimes shake the projector in my theater just enough to bug me. I really like the effect of it , so does my family. They say it feels like it is about to land in the room. I love this hobby... any how I would like to fix the shake in the projector because I really want to turn the sub up and see what this can do.
post #2 of 20
I am worried about this too!!!
post #3 of 20
Thread Starter 
I forgot to mention two of the four screws mounted in the ceiling are in line in one of the joists. The other two are anchored through the dry wall. I am thinking maybe about running a brace using 2x4 between the joists on both sides and mounting the other two screws in the 2x4 insted of dry wall. Do you think this would work? Don't want to do it if the result will be the same.
post #4 of 20
Man Mine is the same mounting as you....I really hope I don't run into the same problem!
post #5 of 20
I am glad I saw this thread because I totally just solved this.

1. I cut my ceiling down and stiffened up the joists with 2X6's. This made it so my projector mount was screwed into solid wood in 3 places. This stiffened it up some. But the thing was still shaking!

2. Cut dowel rods to length to go between my projector and the ceiling, basically giving the projector support on all 4 corners. This worked and helped some, but the result was the LENS of the projector was shaking while the housing wasn't.

3. Thanks to the suggestion of a forum member, I cut a foam disk like a donut, compressed it pretty hard, and shoved it around the lens of the projector with a screwdriver. I have SVS too, so I basically just cut 2-3 inches off the end of a port blocker, cut the center out, and cut it like a "C". And then compressed this into the space of less than half an inch around the lens. This is what really solved the issue.

So, I guess I'd try # 3 first. I think it was the lens shaking inside of the projector. My projector has lens shift, so it is really made so that lens can move around. Doing this also solved my issue of the lens shifting when my son was jumping around upstairs too.

I think all of these things helped, but def # 3 is the one that sealed the deal. If you want pics of any of this I can take a shot of my setup when I get home. The dowel rod thing sounds funny, but it actually looks fine. I painted them black and put rubber ends on it. Makes the whole setup pretty solid.

Before I did this my dual PB12s were shaking my image up onto the ceiling that thing was moving so much. Now I can see a tiny bit of movement, but only when it hits really hard.
post #6 of 20
Thread Starter 
My projector has lens shift too, It is the ae2000. It looks like I will try #3 first then this weekend and replay that sceen where I noticed it. anyhow the pics would be great if you can post them up later, Thanks for your time.
post #7 of 20
I would put your hand on the projetor lightly during a scene that cause the shake to see if the housing is shaking.

It doesn't sound like your mounting is entirely solid. With the projector only screwing into one joist it would be pretty easy for it to have a little bit of movement rotationally around the length of the joist.
post #8 of 20
Quote:
Originally Posted by jayrader View Post

Thanks to the suggestion of a forum member, I cut a foam disk like a donut, compressed it pretty hard, and shoved it around the lens of the projector with a screwdriver. I have SVS too, so I basically just cut 2-3 inches off the end of a port blocker, cut the center out, and cut it like a "C". And then compressed this into the space of less than half an inch around the lens. This is what really solved the issue.

That was me
Glad my idea about cutting the port blocker and stuffing it around the lens is working for other AVSers. I have twin SVS PB12+2's and this solved my lens shaking problem by 95%. I also tried joist stiffening, dowel rods, etc. - but nothing seemed to help at all. In fact - those modifications (in my case) actually made the lens shaking worse!
post #9 of 20
Quote:
Originally Posted by John Ballentine View Post

That was me
Glad my idea about cutting the port blocker and stuffing it around the lens is working for other AVSers. I have twin SVS PB12+2's and this solved my lens shaking problem by 95%. I also tried joist stiffening, dowel rods, etc. - but nothing seemed to help at all. In fact - those modifications (in my case) actually made the lens shaking worse!

True enough, and I never really thanked you. So thank you!
post #10 of 20
Thread Starter 
hey guys I would like to see some close up shots of the port blocker around the lens, I checked out the area around my lens and it would be a very tight fit. I have a panny ae2000u and the lens on it is quite large. I cant put my finger around the area where it looks like I would need to place the foam. This sounds like a great solution but I don't know if I need to shove it in there in pieces. Pics would be great. Thanks.
post #11 of 20
I'll grab my camera tomorrow and do some shots for you. But on mine, the gap is very small also. I mean less than half an inch. So it took some doing but with a flathead screwdriver I slowly worked my way around and crammed about a 3 inch thick piece of stuff in there. And then after that I actually did another inch. It was a bit scary but I didn't hear anything breaking. The result is that lens is really firm in there.

I thought about doing it in pieces also, but decided against it. It seems if I want to pull it out of there it will be alot easier since its in one piece.
post #12 of 20
Jayrader:

Could you post a pic or two with details about how you did the foam and what foam you used, etc? I'm having this problem even after spanning a glue-lam beam between the joists so it doesn't touch the ceiling joists or flooring above, when people bounce around upstairs or slam a door. I have the AX200 with lens-shift and it didn't occur to me it might actually be the lens shaking.

Appreciate the help!

Equusz
post #13 of 20
I wouldn't advise shimming foam in between the lens and housing on your PT-AE2000U. If somebody accidentily hits the zoom buttons the remote, you could end up stripping the gear on the motor that powers the zoom, or worse.

The best way to reduce the shaking is to increase the mass of the unit and/or mounting system that is suspended below the ceiling. You could suspend 4 pieces of threaded screw from the ceiling, and attach a 1/4" steel plate at the bottom making a "shelf". Then set the projector on the suspended shelf.

Greg
post #14 of 20
I see what you're saying, but I don't see how that would work. I mean, the projector is already mounted with a small steel plate which is screwed directly into the beam...seems like a suspended shelf like you describe would "swing" more. Can you clarify?

Equusz
post #15 of 20
Quote:
Originally Posted by hammong View Post

I wouldn't advise shimming foam in between the lens and housing on your PT-AE2000U. If somebody accidentily hits the zoom buttons the remote, you could end up stripping the gear on the motor that powers the zoom, or worse.
Greg

I would say you are right here, but you could firm up the assembly within reason. Push some foam in there, but make sure the zoom and everything still works. Obviously if you cram it in there so tight NOTHING can move you're going to break things.

The reason I think its a good way to go, is because this is the single thing that made the biggest change in my vibrations. I think if I would have made this step first I could have skipped all of the other painful stuff, such as cutting out the ceiling and trussing up the ceiling with 2X6's.
post #16 of 20
Quote:
Originally Posted by Equusz View Post

Jayrader:

Could you post a pic or two with details about how you did the foam and what foam you used, etc? I'm having this problem even after spanning a glue-lam beam between the joists so it doesn't touch the ceiling joists or flooring above, when people bounce around upstairs or slam a door. I have the AX200 with lens-shift and it didn't occur to me it might actually be the lens shaking.

Appreciate the help!

Equusz

I'll try to take some pics for you in the next day or 2. I'm down with a broken leg right now so it will be kinda hard. But I'll have the wife help me.
post #17 of 20
Ouch! Well anything you can do will be appreciated. Also, what kind of foam, how thick, etc.

Careful with that leg!
post #18 of 20
Quote:


I forgot to mention two of the four screws mounted in the ceiling are in line in one of the joists. The other two are anchored through the dry wall.

That's a big no-no! Anchoring a projector mount in drywall shouldn't be done. I believe someone here mentioned they had the same problem before they mounted a support between joists to solve the problem. On new construction jobs we typically over-brace for a projector mount and even craft a 1/2" piece of MDF and router the edges and mount the projector mount to it. Never encountered the problem again.....But, I would like to as that would take some serious bass to vibrate the projector.
post #19 of 20
I have a JVC projector and had a similar shaking problem. I just put a small folded piece of black serviet/paper in between the lense and the casing. ALL problems are gone and I can still adjust lense without any problems.
Regards
Martin Lynge
post #20 of 20
Did you put it between the focus ring and projector case or somehow between the lens and the focus ring?
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