Distance for ceiling mouted projector

The Cat

Novice Member
I've just received my first projector and 120" screen. I planned to fix the screen to the wall in the lounge and mount the projector to the ceiling to give a 120" image. I've quickly come in to a number of issues. From the research I've done I believe I need to calculate a number of parameters including the viewing distance, the throw distance, the vertical offset, the centre point between the projector and the screen (width), the distance either the projector or the screen needs to be from the ceiling (less the vertical offset) and it seems like there will be various other measurements needed to calculate the exact position of the projector itself. I'd like to mount the screen in the middle of the wall due to limited room but this seems to put massive pressure on the exact position of the projector.

Viewing distance: 2.7 - 4 m (9 - 13 ft)
Throw distance: 4.19 m
Vertical offset: -3" (105% so 5% of height (59") = 3" top screen to centre lens)


The first problem I have is that the viewing distance is less than the throw distance! So impossible to have the projector placed low, say on a table? (As the projector would need to be behind the sofa)!?

Scondly for ceiling mounting, if the throw distance, height and horizontal position of the projector needs to be to the cm, will plasterboard be sufficient to hold it? The projector weights 3.473 kgs (7.657 lbs) which doesn't include the mount (not yet purchased). If the projector needs to be fitted to a joist it will be extremely unlikely the joist will be in the perfect position (maybe either distance or width can be achieved depending on which way the joists run but that's just one of 3 parameters). How do people usually deal with this issue? Can you get fully adjustable mounts (height/width/distance?). Or do I need to get someone in to pull the ceiling down to fit a stronger board and then replaster and paint?

The projector has no lens shift (vertical or horizontal) and I hear keystone adjustment is a big no no for trying to get the best quality for your money.

Any tips or advice as this is all new to me and wondering if I'm missing something.

Thanks
 

3rdignis

Active Member
If you already have your stuff.

Put your projector on the floor and project a 120" picture onto the wall. (Closer to screen = brighter / further away = more contrast

This way the floor and ceiling are reversed so you can figure placement.

Set distance limits with zoom.

Set height of projector from floor. (Gives mount drop distance)

I assume you have pull down screen - once fitted should have some side to side and up/down adjustment.

So set screen, diagonal corners should measure the same and level.
 

3rdignis

Active Member
Make sure you can clear the tops of your heads.

You can bolt projector underneath a rear shelf if distance allows.

:)
 

The Cat

Novice Member
If you already have your stuff.

Put your projector on the floor and project a 120" picture onto the wall. (Closer to screen = brighter / further away = more contrast

This way the floor and ceiling are reversed so you can figure placement.

Set distance limits with zoom.

Set height of projector from floor. (Gives mount drop distance)

I assume you have pull down screen - once fitted should have some side to side and up/down adjustment.

So set screen, diagonal corners should measure the same and level.

This is where I'm slightly confused I thought these online calculators tell you the mandatory throw distance? For a 120" screen the projector has to be 4.19m. How does the brighter/contrast work with changing the throw distance? Doesn't that decrease/increase image size? Sorry amateur questions I know

Thanks
 

The Cat

Novice Member
Make sure you can clear the tops of your heads.

You can bolt projector underneath a rear shelf if distance allows.

:)
Hopefully I can calculate the position needed for mounting the projector on the ceiling I just wondered if people bolt to joists or plasterboard and if its joists, how do you get the projector in the exact spot?
 

3rdignis

Active Member
For the same size screen.

Projector further back = more contrast.
Projector closer = brighter image.

It's mild anyway don't worry about it.
 

Joe Fernand

Distinguished Member
AVForums Sponsor
You tend not to ‘bolt’ an overhead projector to anything other than a ceiling mount and the ceiling mount is not mounted to the plasterboard!

You figure out the best option for your ceiling and usually mount the ceiling mount to a piece of MDF spanning your joists (which you may install within the ceiling void to keep things looking tidy) and then position the ceiling mount to ensure the lens is centred on the screen; which may mean an offset installation depending on where the lens is on your projector (you centre the lens on the screen not the projector).

Joe
 

The Cat

Novice Member
For the same size screen.

Projector further back = more contrast.
Projector closer = brighter image.

It's mild anyway don't worry about it.
I've just downloaded the manual and had a quick search on Google. I think I understand what you mean now. The throw has a range based on the zoom used so there's some margin with the distance! Wide - Tele is 3.98 - 4.38m. Thanks for your help.

Oh any opinions on ceiling brackets?
 

The Cat

Novice Member
You tend not to ‘bolt’ an overhead projector to anything other than a ceiling mount and the ceiling mount is not mounted to the plasterboard!

You figure out the best option for your ceiling and usually mount the ceiling mount to a piece of MDF spanning your joists (which you may install within the ceiling void to keep things looking tidy) and then position the ceiling mount to ensure the lens is centred on the screen; which may mean an offset installation depending on where the lens is on your projector (you centre the lens on the screen not the projector).

Joe
Thanks for the post, this all makes sense
 

markie4tv8699

Active Member
I've just received my first projector and 120" screen. I planned to fix the screen to the wall in the lounge and mount the projector to the ceiling to give a 120" image. I've quickly come in to a number of issues. From the research I've done I believe I need to calculate a number of parameters including the viewing distance, the throw distance, the vertical offset, the centre point between the projector and the screen (width), the distance either the projector or the screen needs to be from the ceiling (less the vertical offset) and it seems like there will be various other measurements needed to calculate the exact position of the projector itself. I'd like to mount the screen in the middle of the wall due to limited room but this seems to put massive pressure on the exact position of the projector.

Viewing distance: 2.7 - 4 m (9 - 13 ft)
Throw distance: 4.19 m
Vertical offset: -3" (105% so 5% of height (59") = 3" top screen to centre lens)


The first problem I have is that the viewing distance is less than the throw distance! So impossible to have the projector placed low, say on a table? (As the projector would need to be behind the sofa)!?

Scondly for ceiling mounting, if the throw distance, height and horizontal position of the projector needs to be to the cm, will plasterboard be sufficient to hold it? The projector weights 3.473 kgs (7.657 lbs) which doesn't include the mount (not yet purchased). If the projector needs to be fitted to a joist it will be extremely unlikely the joist will be in the perfect position (maybe either distance or width can be achieved depending on which way the joists run but that's just one of 3 parameters). How do people usually deal with this issue? Can you get fully adjustable mounts (height/width/distance?). Or do I need to get someone in to pull the ceiling down to fit a stronger board and then replaster and paint?

The projector has no lens shift (vertical or horizontal) and I hear keystone adjustment is a big no no for trying to get the best quality for your money.

Any tips or advice as this is all new to me and wondering if I'm missing something.

Thanks
Joists ar approx 16 inches apart, what I had to do was mark the two joists that fall within your throw distance ( we will say 11/12 feet) i placed a board between the two joists , screwed to both joists. This gave me 16 inches to play with on my projector placement.
 

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