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Discussion Starter #1
Guess what, another Dell LT-150 question......

I am looking to mount my LT-150 high up since I have no other option. I am basically going to put a shelf against my back wall which will be directly above my couch. The projector will be about 6' off the ground or 2.5' above my head. My screen will be ceiling mounted and my ceiling is 7'. I am worried about fan noise.

My question is:

Can I mount the projector right side up, tilt it downwards (by raising the back feet) and use keystone correction to make it square without a detrimental effect on picture quality?

I want to avoid "flipping" the projector so that I can avoid having the fans kick up.


Thanks,

Dino


[This message has been edited by DinoT (edited 08-01-2001).]
 

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Hey Dino.


You will have to flip the projector if you ceiling mount it. No way around this unless you want to start playing with mirrors. The kick up in the fan noise is a higher pith more than so much louder.


Now the important part. When you mount the LT150 on the ceiling, it has to be inverted, but the image also shoots down some what. Check the owners manual and they will show you a diagram about what I am talking about. For example...

On a 100 inch screen, the top of the image is 10 inches down from the ceterline of the lense.


In your case... lets say the projector is mounted square agaisnt the ceiling flush. No drop down. You image would start about 1 foot down from the ceiling at 100"s. This puts the top of the picture from the LT150 right at 6 ftt from the floor.


Is table mounting an option?
 

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Discussion Starter #3
Darian,

Thanks for the reply. When you say that there is no way around inverting the projector for a ceiling mount do you mean that for reasons of picture quality? I am asking because I was able to place it high (by holding it) and angle it downwards. With some keystone correction I was able to get the sides straight. Now, because I was holding it and because I wasn't really displaying onto something which could help me judge the picture quality I don't know how much the picture quality suffers. I had read somewhere that keystone correction has an adverse effect on picture quality.


Thanks,

Dino
 

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Once you start messing with the thing like that you will notice that edge to edge focus is gone.


The other reason the fan speeds up is because the heat can't go up and away from the projector. Hence the fans have to push the hot air further away.


Need help with a hush box?
 

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Discussion Starter #5
Darian,

Thanks for the reply. I am not really looking at a hush box for now because my projector will be flush up against my back wall. To be honest with you I wasn't planning on getting a projector until I had a new house built. I could not pass up $1700 for an LT150 though. So I have to make do with my current home. My wall is exactly 11'8" from my screen. This will put the projector lens around 10'10" from the screen. Perfect for a 100" diagonal picture.

What I am thinking about doing is rather than making a little shelf for the projector I will make a really long shelf. It will be an 8' wide shelf that will run along the back wall about 5" from the ceiling. This will leave a 3" gap between the top of the projector and the ceiling. Hopefully it won't overheat up there. I might add a small dc fan up there if it heats up. The shelf will be over my couch. I am hoping to use this longer shelf as somewhat of a sound barrier since the shelf will block direct noise from the fans to my ears. Even if it lowers the fan noise by a few db's I will be ok.


Do you have an HD receiver? If so what can you receive from Gaithersburg? I am lookng at areas to move to. Because Howard County has gotten out of control (pricewise) I am looking at northern Montgomery county. Damascus is a possibility right now. Currently I am in a good location as I get all the Baltimore and all the DC DTV stations over the air.


Dino www.dinotheo.com
 

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Darian,


I'd be very interested in your ideas for a hush box. I have to set up a LT150 at a friends house, and I have a feeling he won't tolerate the fan noise.


Love to hear what you have to say so I don't waste my time on unproven designs.


regards,

chris
 

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A basic hushbox should be pretty simple to build. First figure out a way to mount the projector against the ceiling, then get a couple of hinges and a latch. Build a box with an open front, and attach it to the ceiling with the hingest on one side and the latch on the other. Make it big enough for good air circulation, and that's it. Line the box with something like ductboard, spray-on duct liner, or TheatreShield.


Now get a cheap radio shack digital temperature gauge and stick it in the box and make sure the ambient temperature is okay. Depending on the location of the projector, this might be all the sound deadening you need. But if you need more, get a piece of optical glass and cover the open front of the box. But once the box is fully enclosed, you'll need to vent the hot air out. So now you'll have to build a muffin fan into the back of the box, with some light ducting to take the air away along with an intake for cool air. There's lots of ways you could do this.


Anyway, that's my .02. I'm about to start building one soon. In my case, I'm going to drywall the box right into their ceiling so it looks nice, so instead of hinging it on the side I'm going to make the front of the box removable to get at the projector, clean the glass, etc. I'm also going to build a cold air return and a duct for venting the heat into the ceiling, and put a temperature controlled fan in it.
 

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Discussion Starter #8
What would be considered the highes "safe" ambient temperature? I am putting a thermometer up there but I have nothing to compare it to.


Thanks,

Dino
 

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I've been thinking about LT-150 mounts tonight, and I think I have a pretty good idea of how to homebrew one.


Bear in mind that I haven't received my Dell LT150 yet.


First, a while ago I think someone posted a message that said that there were mounting holes on the bottom of the LT-150 under the feet, one in each corner. You have to remove the feet or a plug or something to find them.


Assuming they are there, I plan to take a piece of plywood, drill it for the holes, and mount the LT-150 to it with long screws, using plastic standoffs over the screws to keep an inch or two of space between the LT-150 and the ply to aid in cooling.


Then, I'm going to use a speaker wall-mount to attach the plywood to the ceiling. I have one here that has a ball joint to allow the plate to swivel in two dimensions for fine adjustment. Then you can lock the ball joint with a screwdriver to hold it in place. It's rated to hold something like 40 lbs.


Voila! Instant ceiling mount for about $20. And you can take down the LT-150 by twisting a single screw. Now, the only thing I'm not sure about is whether this thing will vibrate while the projector is operating. If so, I'd use rubber biscuits in the corners between the plywood and the ceiling and friction-fit them in place after the projector has been adjusted. The whole assembly will hang maybe 6" from the ceiling, and the projector will be maybe an inch below the plywood.


Can anyone see a problem with this mounting scheme?
 

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Quote:
Originally posted by dhanson:
Can anyone see a problem with this mounting scheme?
I'd bet it would work fine. You want to keep the projector horizontal so you don't need to use keystone correction. The only question would be if the speaker mount is long enough to give you the drop you need. BTW, there's a third mounting hole used by the "mystery screw" under the lense.


------------------

Tom L.

NEC LT150 FAQ

My stuff, pictures, HTPC, and screen tests
 

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I mounted my new LT-150 last weekend and it has been working great. Here is what I did:

- Go to Lowes/Home Depot and visit the plumbing department pick up two 1.5" flanges and a 1.5" nipple the length that you want the projector dropped from the cieling. This is your drop down and will give you a solid place to mount the speaker mount.


- Then get a few packages of different length 4mm screws (the mounting holes all have different depths)


- Get a bunch of nylon washers (to seperate the mounting plate from the projector for cooling)


- I picked up a small sheet (18"X6") of sheet metal to make the mounting plate.


- Mount the large part of the speaker mount to the bottom flange and the "ball" part to the mounting plate.


- Attach the mounting plate to the projector using the three appropriate mounting screws and the nylon washers


- Now put connect the projector and mounting plate with the one screw of the speaker mount.


- Before drilling any holes in the cieling line up the projector lens with the exact center of the screen so that you do not have any side to side keystone. (I did not do this and after mounting it the first time realized that the lens was not on center with the drop down pole). And since there is no zoom get it the correct distance from the screen.


- Now remove the projector from the assembly (with the one screw on the speaker mount) and carefully put it away while you mount the drop down to the cieling.


- Re attach the projector, line it up and enjoy.


- This is much easier if you have someone to help you line up the projector.
 

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Answers:

Do I have a HD receiver? Yes

I have the DiSH 6000 with the OTA mod. I have channels:

HBO HD / Showtime HD / DiSH Demo From Sat

NBC HD/ ABC HD (still 4:3 those pricks) / Fox HD / CBS HD and WETA HD All from DC off air.

4/5/7/9/20/26/45/50 Off air in SD mode.

I can receive Baltimore stations if I reposition my antenna. I mostly stick with DC.

UPN 20 was going to be HD by now but that tower shut down in DC screwed me out of HD Enterprise on Sept 26.


Hush Boxes. My is designed to either be vented into the ceiling or into the room. Into the ceiling will require me to run some flex duct to and from the location. INroom isa a different front face with push pull fans. Enclosure is made out of .25 Acrylic. I used black to give it a slightly more built in rather than slapped on look.


I was going to use IR permeable Acrylic. This stuff looks black but IR codes go right into it. I decided not to sue this stuff when I determined that I had to hold down the power button for the 150 to shut it off. I decided to insulate the inside of the box with Sonex products. This stopped the sound of the projector dead. I could have gone with thicker Acrylic and may just use thick IR passable material in the future.


Optical glass is a must.


Here is one of the secrets to air flow in the hush box. If you can get 45 CFM passing the box doesnt warm up at all. The sonex that is ~3 inches away from the projector vents does not feel warm to the touch after 6 hours of operation.


I have yet to decide if I want to do the ceiling venting. This will require a little more work but it makes the unit dead silent. In room venting is quite but not silent.


How much work do I want to do to get it quite.


How much did I spend on the audio in this room again???
 

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As for IR, another way to go is to run a CAT-5 into the hush box, then get a cheap Niles or Xantech 4-port Infra-red extender system. Put an emitter inside the box, and mount the sensor in front of your screen. Then you can just aim your remote at the screen to control the projector. Total cost for that shouldn't be much more than $150 or so. Wiring might be a hassle for existing construction, but if you're building a theater make sure you run low-level wiring to your hush box and the screen wall for such a system.
 
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