CurtPalme.com Home Theater Forum

gksottawa · Joined: 09 Dec 2011 Posts: 6

Hi

I've recently bought the Sony IFB HDMI input card for my 1271Q. The Sony installation manual contains the table for the picture sizes and the corresponding distances of the projector from the screen based on 4:3 AR.

Therefore, for a given picture width (16:9 AR) I'd appreciate if someone can tell me how to calculate the distance of the projector from the screen with the HDMI card installed.

Regards
GKS

**kal** · Posted: Fri Dec 09, 2011 5:31 pm Post subject:

I'm moving this thread to the CRT projector forum.

Throw distance is not related to the type of input card used.

For more info on how to set the proper throw on any CRT projector, see the bottom of this page: http://www.curtpalme.com/TubeCondition_PoorInstall.shtm

To quote:

While following the manual for throw distance is always a good bet (and recommended for new users), to maximize tube life even further do the following steps:

- Put the projector on the cart or simply leave it on the floor so that you can move it.
- Display something that fills the screen entirely (like a grid test pattern).
- Using only the green (middle) tube, look into the tube and increase the image width on the tube face until it is around 1/8" to 1/4" from the edge of the white phosphor. Under no circumstances should you allow the image to go off of the white phosphor surface!
- Move the projector back and forth until the image fits your screen.

THAT is the correct throw distance for optimal phosphor usage.

It'll usually be 5-8% closer than what the manual tell you because the manual throw instructions are conservative since they make you install blindly without even looking in the tubes at all.

Kal

gksottawa · Joined: 09 Dec 2011 Posts: 6

Thanks I appreciate the reply.

May be I didn't phrase the question right. My understanding is that the projector can display 1600x1200 image and the card IMO must be changing the resolution to 1920x1080 for 1080p HD content. Therefore, the question is if I had a 120" wide and 90" high image for the 4:3 DVD content would the HDMI card still be able to maintain the image width to 120" (albeit the height would be 67.5") for the 16:9 1080p HD content at the same projector distance.

Regards
gksottawa

**kal** · Posted: Fri Dec 09, 2011 6:35 pm Post subject:

Hi,

The card does not scale or change the resolution in any way.

On that projector I would limit the resolution to 1080i. While it may be able to sync to 1600x1200, it'll look like crap. Not to mention there's no source out there (other than a PC) that can output that resolution.

A 120x90" screen is really huge for that projector too. You may find the image too dim. Just a heads up.

Don't confuse aspect ratio with resolution. The two are not related. Pixels are not (and don't need to be) square.

Kal

gksottawa · Joined: 09 Dec 2011 Posts: 6

So is the manufacturer's claim misleading that the card supports 1080p on this projector. That's the reason I bought it so that I can connect bluray player to watch 1080p content Sad

Regards
gksottawa

**kal** · Posted: Fri Dec 09, 2011 7:01 pm Post subject:

Nothing misleading about it.

Your projector can and does indeed do 1080p and could do that even before you added the HDMI card. You could feed a 1920x1080 resolution from a PC (for example). How well your projector does 1080p has nothing to do with this input card.

The order page does say:

"Add digital HDCP-compliant HDMI 1.3 inputs allowing you to watch hi-def content at up to 1080p resolution!"

The card will allow you to watch up to 1080p on your projector from HDMI sources so it is your best option for watching HD content on that projector. I'm just saying that you probably don't want 1080p on that projector because, regardless of how you get 1080p into that projector, the tubes & electronics in that projector cannot fully resolve 1080p. 1080i will look better to you (probably). Try both and see. Regardless of which you choose, you basically still need an HDMI input on the projector to watch HD of any sort since HDMI is pretty much the only way to get HD these days.

I think you're possibly confusing the issue as well in wanting 1080p. Both 1080i and 1080p are 1920x1080 resolution. They are the same resolution. 1080i is interlaced (requires 2 passes to paint the picture) while 1080p is progressive (requires 1 pass to paint the picture).

My projector is a Barco Cine 8 Onyx machine that is higher end than your Sony with better (sharper) resolving power. Even though mine also supports both 1080i and 1080p I run it at 1080i as it looks better as it requires half the bandwidth so the projector is not working as hard. Easier to get set up and converged as well.

Kal

gksottawa · Joined: 09 Dec 2011 Posts: 6

Thanks again I appreciate it.

However, I am still struggling with the original question. Would the projector maintain the same image width (from the same distance) with this card if let's say my current setting is to watch 4:3 DVDs via the RGB input. This is because I would like to avoid readjusting the projector.

Regards
gksottawa

**kal** · Posted: Fri Dec 09, 2011 8:00 pm Post subject:

gksottawa · Joined: 09 Dec 2011 Posts: 6

Thanks

Let me collect the data and get back with you in a couple of days.

Regards
gksottawa

**AnalogRocks** · Posted: Sat Dec 10, 2011 1:25 am Post subject:

Set your 1271 up with 1080i, and maybe 720p if your tubes are good. Yes it will stay in one place once you set it up. Do a 7 foot wide image with that. Anything more tends to wash out, even if you drive your tubes to the max.