Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

BG808 ceiling mount question

 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Design & Construction
View previous topic :: View next topic  
Author Message
keldor



Joined: 04 May 2007
Posts: 32
Location: Waterloo Ontario


PostLink    Posted: Wed Aug 29, 2007 7:04 pm    Post subject: BG808 ceiling mount question Reply with quote


        Register to remove this ad. It's free!
I have run the barco "Lens.exe" program and I am looking for some confirmation in regards to the numbers it is giving me. Some background fiirst. I am building my HT in a basement room. My room is approximately 18' long 12' wide and 7.5' high. I am thinking about a 96" wide 16x9 screen. Because of my relatively low ceiling I was hoping the I would be mounting the Barco as tight to the ceiling as possible. When I plug the SW= 96" screen width into the Lens program it gives me an "A" value of -7.5. If I understand the program that is suggesting that the Barco needs to be hung 7.5 inches below the ceiling just to have the screen flush with the ceiling. Can anyone confirm or comment. Thanks guys!

Steve

_________________
"It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." Carl Sagan
Back to top
jask



Joined: 17 Mar 2006
Posts: 8836
Location: kamloops BC


PostLink    Posted: Fri Aug 31, 2007 4:35 am    Post subject: Reply with quote

no I think what it is telling you is that the barco needs to go 7.5" -INTO- the ceiling!
I know this because my room is about the same size and I made an opening in the ceiling that leaves the lenses almost flush with the ceiling, basically framed an opening like a stairwell-doubles joists and headers and an additional 2 layers of 3/4" plywood to decrease deflection from above.
Back to top
View user's photo album (4 photos)
keldor



Joined: 04 May 2007
Posts: 32
Location: Waterloo Ontario


PostLink    Posted: Fri Aug 31, 2007 12:38 pm    Post subject: Reply with quote

jask wrote:
no I think what it is telling you is that the barco needs to go 7.5" -INTO- the ceiling!
I know this because my room is about the same size and I made an opening in the ceiling that leaves the lenses almost flush with the ceiling, basically framed an opening like a stairwell-doubles joists and headers and an additional 2 layers of 3/4" plywood to decrease deflection from above.


Thanks Jask. Did you sink it into the ceiling to get the screen at a particular height or just to get the projector out of the way? If I have it backwards then it simply means that if I mount right at the ceiling then then the top of the screen will be 7.5" below the ceiling. That would probably be a reasonable location.

Steve

_________________
"It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." Carl Sagan
Back to top
jask



Joined: 17 Mar 2006
Posts: 8836
Location: kamloops BC


PostLink    Posted: Fri Aug 31, 2007 6:15 pm    Post subject: Reply with quote

I put it into the ceiling to maintain MAX. screen size. The problem with mounting in "on" the ceiling was that it limited the Max screen size( unless I wanted the bottom edge of my image 14" off of the floor,and to move the front row back 3+ feet. Headroom was also a consideration as my back row will have a riser
Back to top
View user's photo album (4 photos)
jowi



Joined: 14 May 2006
Posts: 83



PostLink    Posted: Thu Oct 11, 2007 1:31 pm    Post subject: Reply with quote

jask wrote:
no I think what it is telling you is that the barco needs to go 7.5" -INTO- the ceiling!

This is wrong. 'Negative ceiling distance' in lens means that the top of the screen is x inches BELOW the TOP of the Barco's mounting brackets...

So, with a negative ceiling distance of 7.5", this means that if you mount the Barco tight against the ceiling, the top of the image will start 7.5" below the ceiling... hence the term 'negative ceiling distance'.
Back to top
faradayblue



Joined: 28 Aug 2008
Posts: 29
Location: Acton, Ontario, Canada


PostLink    Posted: Thu Aug 28, 2008 3:14 am    Post subject: Reply with quote

I'm installing a 94.5" wide screen and a Runco DTV 1100 in my basement HT that has a 7' 3" ceiling.

The Barco 1209s installation manual defines the following relationship: CD=B+A where
CD = the distance between the ceiling and the projector mounting surface
B = the distance between the ceiling and the top of the projected image
A = the correction factor

The Barco projector software calculates a correction factor of A=-8.2" and a projector distance PD= 135.4" from the screen to the projector mounting surface for the 1209s projector with a 16:9 screen of 94.5" width.

If I mount the DTV 1100 as close to the ceiling as possible using the factory mount which is attached to a 1/8 in steel plate attached to 3 joists on my ceiling then CD= 2.25". From the relationship CD=B+A, the value of B=CD-A or specifically in my case B=2.25-(-8.2)=10.45". Hence the top of the image on my screen should be 10.45" from the ceiling.

If I'm wrong please let me know so I don't mess up my installation.
Back to top
keldor



Joined: 04 May 2007
Posts: 32
Location: Waterloo Ontario


PostLink    Posted: Thu Aug 28, 2008 1:32 pm    Post subject: Reply with quote

faradayblue wrote:
I'm installing a 94.5" wide screen and a Runco DTV 1100 in my basement HT that has a 7' 3" ceiling.

The Barco 1209s installation manual defines the following relationship: CD=B+A where
CD = the distance between the ceiling and the projector mounting surface
B = the distance between the ceiling and the top of the projected image
A = the correction factor

The Barco projector software calculates a correction factor of A=-8.2" and a projector distance PD= 135.4" from the screen to the projector mounting surface for the 1209s projector with a 16:9 screen of 94.5" width.

If I mount the DTV 1100 as close to the ceiling as possible using the factory mount which is attached to a 1/8 in steel plate attached to 3 joists on my ceiling then CD= 2.25". From the relationship CD=B+A, the value of B=CD-A or specifically in my case B=2.25-(-8.2)=10.45". Hence the top of the image on my screen should be 10.45" from the ceiling.

If I'm wrong please let me know so I don't mess up my installation.


You are correct. The -8.2 value for "A" means that if your projector is flush with the ceiling then the top of your screen should be at 8.2" below the ceiling.

Keep in mind that this will give you factory default raster size. If you want to maximize phosphor use then this is not the way to proceed. This was the piece of info that I did not realize when I mounted my 808. Not a big deal for me but many here would highly recommend maximizing raster size.

Cheers,
Steve

_________________
"It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." Carl Sagan
Back to top
jkruger



Joined: 24 Oct 2007
Posts: 2435
Location: Carlsbad, CA


PostLink    Posted: Thu Aug 28, 2008 1:59 pm    Post subject: Reply with quote

With the rasters opened up on my 1209s I had to drop the rear of the projector to get the keystone out of the image. Luckily I have a high ceiling mounting area and was able to mount the screen and projector fairly high. The lenses are actually lower than the top of the screen and the projection angle is nearly equal to the viewing angle. This would be tough to do with a 7 or 8 foot ceiling. I have not finished setup with the new larger screen yet so these angles may change. I'm using unistrut for the mount so it is very adjustable.
Back to top
faradayblue



Joined: 28 Aug 2008
Posts: 29
Location: Acton, Ontario, Canada


PostLink    Posted: Tue Sep 09, 2008 12:51 am    Post subject: Reply with quote

I assume that if greater raster area is used the projector would need to move closer to the screen. If this is the case the mounting position of the projector is constrained by structural elements in my room. I suppose the screen could be brought closer to the projector. I recently installed the projector and have attached a photo.


Installed.jpg
 Description:
 Filesize:  112.84 KB
 Viewed:  6426 Time(s)

Installed.jpg


Back to top
VideoGrabber



Joined: 09 Apr 2006
Posts: 933
Location: Michigan


PostLink    Posted: Tue Sep 09, 2008 6:59 pm    Post subject: Reply with quote

Very clean install, fb. I'd recommend moving the screen a few inches closer, if possible. Your phosphors will thank you for it, with increased lifespan and greater brightness (at a given drive level).
_________________
- Tim
Back to top
kal
Forum Administrator


Joined: 06 Mar 2006
Posts: 15747
Location: Ottawa, Canada

TV/Projector: JVC DLA-RS56


PostLink    Posted: Tue Sep 09, 2008 8:43 pm    Post subject: Reply with quote

Yup. You look like you could go 4-6 inches closer. The other option as you mentioned is moving the screen out (actually quite simple - just use some blocks or offsets).

Kal

_________________

Support our site by using our affiliate links. We thank you!
My basement/HT/bar/brewery build 2.0
Back to top
View user's photo album (18 photos)
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Design & Construction All times are GMT
Page 1 of 1
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum