CurtPalme.com Home Theater Forum

dc_pilgrim · Joined: 31 Oct 2006 Posts: 225 Location: PA

I am getting ready to let the sheetrockers in to do their thing. My PJ hanging plan is to attach strut to the joists (done), allow RSIC clips and hat channel to ride over the strut, attach drywall to the channel, with only threaded rod penetrating the drywall. Then attach another bit of strut channel to the threaded rods, and the PJ to that. This diagram is crude, but hopefully effective:

My question is, I have 3/8" threaded rod in 2 foot lengths. From a mechanical setup (and practical) perspective, should I trim these down to make the PJ flush with the ceiling? Should I let it hang a little (airflow?), a lot (minimize keystone - am I saying that right?). The primary seats will be directly beneath. Making more headroom more desireable.

At this point I am leaning towards attaching the full 2' rods and only triming them after the drywall is up. I was thinking I should add lock-tight (is that the right product) or something to the strut channel nuts - good call or bad. There will be 6 threaded rods coming from 3 pieces of strut.

Any comments or hints. I am new to all this (CRT, construction, etc), so no point is too obvious. Any provision for hoisting I should make? I was thinking of the chains or strap method when the time comes (w/plywood underneath PJ), affixed to the hanging strut.

Thanks, Dave

dc_pilgrim · Joined: 31 Oct 2006 Posts: 225 Location: PA

Well, wound up only finding 3 of my threaded rods, and turns out they were 36". I cut them in half to 18", and mounted them. Sheetrock crew is coming today to install RSIC clips and sheetrock. Hope I got things right. I am imagining I will wind up trimming these back when it comes time to hang the pj. The rods cut pretty easy with a hack saw, so it shouldn't be too bad.

I ran 2" flexible conduit to the PJ also. Will trim that back later also. Wasn't sure what the finished distance would be since the RSIC clips were put off till last by my carpenter.

Jesse S · Joined: 12 May 2007 Posts: 209 Location: Etobicoke

I have the same pj hanging now using unistrut. The length really depends on the ceiling height and where you want the screen height. I have 8' ceilings and the rod is about 6-8" long but the pj is tipped downward somewhat. That puts the screen about 3' from the floor up to 6.5' or so. Basically, if you mount the pj right up at the ceiling and with no tilt, the top of the image will be almost at the ceiling height (minus the 2 strut heights).

Clarence · Posted: Mon May 14, 2007 11:56 am Post subject:

jask · Joined: 17 Mar 2006 Posts: 10165 Location: kamloops BC

the NEC setup manual does not show any required drop for your scree size. are you talking about 7ft diagonal? if so it suggests for an 80" diagonal screen 101 13/16ths"lens to screen center-29 7/8ths" ceiling to screen center-and 99 15/16ths" lens to screen surface...based on horizontal ceiling mount..
The optimum viewing angle is the same as the projectors angle...so if the pj is parallel to the ceiling it will throw the image at 11degrees above horizontal the reflected angle will be 11 below horizontal. you can do the math from your ideal viewing position to see how high the screen center should be, but with 8 ft ceilings I think it will need to be mounted as high as you can get it and the screen will look high on the wall but viewing from 8-1/2 ft from the screen this creates an idea viewing position somewhere around 2 feet off the floor Very Happy

I have cut my floor joists and essentially framed a stairwell opening so that I could stuff the pj up another 8-9 inches and this puts the lenses very near the surface of the ceiling 8) my wifes only concern was this was almost directly under the kitchen fridge!

**AnalogRocks** · Posted: Tue May 15, 2007 6:06 am Post subject:

dc_pilgrim · Joined: 31 Oct 2006 Posts: 225 Location: PA

Okay -

Well, I trudged through and the PJ is up. My carpenter's volunteered to heave it up, I was 400 miles away.

When I was getting the strut up post drywall I realized I made a mistake on the way. I had spaced the strut at the width of the PJ. I should have gone wider or shorter. so I could drop in some side to side struts, then the final ones. Instead I just mounted the struts I had to the ones I had attached to this side of the drywall - with the longer struts serving to spread the weight over more joists (I hope). Could hold me swinging from them, and I weigh more than the PJ, by a good margin. So no side to side, and I am an inch or two off center, but its up. (The lenses are off because I sold them, only to realize my cheap parts machine had pristine tubes, I'll move the lenses from my other 6PG+ when I get home).

My new question is, is the caboose supposed to drop like this?:

Closer shot:

Clarence - your thread tip is a good one. I struggled with that issue, but the sawzall gave me a cleaner cut, and let me get things to work.

Jask - it will be a 7 foot wide, 92" diag - - maybe bigger, like 100", we'll see once we are running. I think the PJ dropping would cause enought problems, no fridge required. I think a couch is above mine though.

Jesse - I think my ceiling is 7'6 (roughly), and my soffit is 10" or so. I have a feeling with the dropped caboose this PJ won't be aimed right. We'll see.

I am travelling through this weekend, so if the PJ isn't on the floor from failure, I guess I'll see soon.

jask · Joined: 17 Mar 2006 Posts: 10165 Location: kamloops BC

I need to check in more often!!
I will try to resize some pics of my install and pm them.
The projector as you probably already know is tipped way too far up! the mounting hole looks too far forward,and the factory mounts also have a second lock screw, the first allows you to pivot to the optimal position and the second allows you to lock the final position.
Do not worry too much, if you have not already fixed it you could mount a second set of 'L" brackets behind the first set in the track but bolt them to the hole in the bracket on the projector . use the nut that goes up into the track to allow it to move up and down by adjusting the nut,this should allow you to tip the front down. All the NEC projectors need a really good installation to allow proper image geometry,make sure you are level (or perpendicular to the screen),square,have the proper vertical offset for your screen size.

dc_pilgrim · Joined: 31 Oct 2006 Posts: 225 Location: PA

No problem Jask - - It has sat in that position for a good month or so. I am not worried about it falling. It tilts easily, and I figured I'll tighten things up when I get a chance to set it up. A second set of brackets isn't a bad idea though.

There to many other projects in the basement, and the family mandate is to get the playroom done first, and then I am allowed to work on my playroom. The target is to have the room running for my daughter's second birthday in October. Seemed like an easy target at first, but now it is looking more challenging.