CurtPalme.com Home Theater Forum

_in_peace_ · Joined: 21 Jul 2009 Posts: 152 Location: Sweden

Hi!

I'm a new-bee in the business Cool

Can i tilt the projector and have it 4 inches under the end of the screen.
Or should I avoid keystone just like on a digital?

Thank's
Mr. Green

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

you can tilt its just that if you want even burn in of the tubes cause you might change your set up in the future then you might not have a clean tube face to work with. otherwise its fine as long as its not too much of an angle. its been discussed here before what the most of an angle you should go but as long as the keystone can cover it then thats your limit, albeit might not be the best solution.

Athanasios

ecrabb · Posted: Sat Sep 05, 2009 2:23 pm Post subject:

What projector? G70? 4" off the edge of the screen sounds like less than "typical" offset. What's your screen size and throw?

SC

_in_peace_ · Joined: 21 Jul 2009 Posts: 152 Location: Sweden

The size of the screen... hm, i think around 94"
The distance is 2.6 m. Yes a G70 Smile

ecrabb · Posted: Sat Sep 05, 2009 4:10 pm Post subject:

OK, so a 94" wide screen and a 2.6m throw - that's almost identical to my setup. For reference, my offset (screen edge to green lens center) is probably pretty close to yours - maybe even a tad more. That's not far from typical.

FYI, the only way to eliminate keystone altogether is to mount (or hang) the projector such that the lenses are centered on the screen with the rear of the projector tilted. Rear-projection setups are the only installation that typically accommodates that setup well.

In short, you're fine.

SC

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

wow, a new guy who actually did his homework and asks intelligent questions. This doesn't happen here very often Thumbs Up

Enjoy the G70, it can throw a really good pic comparable to a $5K digital.

ecrabb · Posted: Sat Sep 05, 2009 5:16 pm Post subject:

Yeah, that impressed me, too.

Hey, wait a second... Did you just compliment a guy on his G70? Uh oh. I need to PM Kal and tell him somebody hacked Dragan's account. Wink

SC

dturco · Posted: Sat Sep 05, 2009 5:38 pm Post subject:

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

hey the guy already bought, it's presumably working, so why pee on his parade. If it breaks down, which it probably will, then I'll be there to recomend a Marquee. Wink

ecrabb · Posted: Sat Sep 05, 2009 10:46 pm Post subject:

_in_peace_ · Joined: 21 Jul 2009 Posts: 152 Location: Sweden

hehe, who is dragan?
thanx fot the answers Thumbs Up

RobertMfromLI · Joined: 29 Jun 2009 Posts: 114 Location: West Islip, NY

in peace:

From what I understand, yes, you can tilt the projector. Yes it will make adjusting it more difficult, and yes, it causes uneven wear (or more accurately non-rectangular wear) on the tube surfaces.

And from what else I have gleaned, it is also more difficult on the projector itself as the guns are bending the image to fit the image rectangularly on the screen. This also seems to cause other issues with the image as pixels are getting "squished" or expanded to make this happen. I could be wrong on this, it's been a while since I have read up on it, but that is my rememberance of what I read.

On a related note, I have a PJ that had a couple failing boards (they worked fine, but solder points were definitely on their way out). When I did something similar, the PJ would complain and report board failures until I restored the settings to midpoints. Shortly afterwards, the boards entirely failed (well, their solder points anyway - easy enough to fix). I am guessing that the greater current draw on the failing connections made them entirely fail. I'd guess that such a continued strain can cause such solder points (good, bad or otherwise) to heat up to the point that such failure will occur at a later date. I am also guessing that such a failure depends on how much of a tilt you are adjusting for (ie: a little or moderate tilt may never cause the problem - while a very large tilt may). Also, my PJ models (BG500/BG800) may have been more susceptible to such failures.

And (everyone) as always, I am hoping for any corrections to my understanding of this - I've got no problems being wrong, as long as someone points it out so next time I am not wrong. Smile

**AnalogRocks** · Posted: Sun Sep 06, 2009 4:29 pm Post subject:

Why not tilt the screen to make it easier for the projector?

matteomo · Joined: 23 Dec 2007 Posts: 11

_in_peace_ · Joined: 21 Jul 2009 Posts: 152 Location: Sweden

matteomo · Joined: 23 Dec 2007 Posts: 11

_in_peace_ · Joined: 21 Jul 2009 Posts: 152 Location: Sweden

ecrabb · Posted: Mon Sep 07, 2009 3:33 pm Post subject:

ecrabb · Posted: Mon Sep 07, 2009 3:47 pm Post subject:

ecrabb · Posted: Mon Sep 07, 2009 3:54 pm Post subject:

A couple more things...

1) My G70 is about 120" from my 96" wide screen, so the throw is about 1.25x screen width. That's slightly inside the PJcalc-recommended distance, because I wanted to be a little more conservative with the raster-maximizing, because I wanted excellent corner focus.

2) My machine is dropped from the ceiling at the front, and raised at the rear to aim tube-center at screen center.

3) I don't remember what my offset is, but I think my green lens-center is probably 6 inches or so outside the screen border. Don't recall what throw angle that represents.

Hope that helps.

SC