Seating position

[Mr A]

Screen to projector distance is discussed quite often on this forum but what is not mentioned is screen to seating position distance. Are there are any guidelines or typical distances away from screens that you need to be other than far enough to see the picture properly.

How far would you need to sit from a 6’ wide screen using a CRT. The projector will initially be fed from Sony 735 using RGB connections. Will it suffer from scanlines?? If so how badly. Barco have informed that I need to mod the h sync input to allow it to fed composite sync from the DVD player, does anyone know how to do this has anyone done it?

[Roland @ B4]

Mr A

There a huge number of calculations that you can use to get the ideal viewing distance. I prefer to sit one and a half times the screen width away.

Using this formula you should be about 9ft from the screen, which should put you right under the CRT projector.

You don't say which projector you are using so it is difficult to say about scan lines. Unless the projector has a line doubler built in or an external scaller you will almost certianly see scan lines.

I asume the RGB connection from the 735 is via the scart connection. I think that the h sync mod Barco refer to is the fact that scart sends no sepaerate sync signals. You have to use the composite sync to get the projetor to lock. I'm not aware of a company that makes Scart to RGB leads so you will have to make one your self.

You would however be far better to use the component outputs if your projector allows this input.


B4

[ 09-07-2001: Message edited by: B4 ]

[Paul D]

Profigold do a Scart to RGB lead(three phonos), but it doesn't work unless you also connect the "composite video out" (yellow phono) from your dvd player to th "H" sync on the projector.
I had to do this with my Sony Vw10ht to get it to sync. ;)

[Arthur.S]

As far as scan lines go, I've been told in the past that for an ideal picture, you should not sit further forward than the CRT projector itself.

[Gordon @ Convergent AV]

I'm afaraid there isn't actually a complete answer or formula for this.

the ideal distance to sit from any screen is far enough away so that you don't see the picture structure. For a CRT projector this is affected by many things. The reality is that you have to "suck it and see". It sounds like you have a "video" only projector so yo're going to be looking at aninterlaced image. Scan line structure will be more obvious with this.

B4's advice is a pretty good rule of thumb until you get up to high grade scalers and projectors when you can sit right in front oif the screen and see no structure. You'll porobably find that you'll have to sit further away than the projector is to screen though in your situation, if we've guessed right. You will, likely as not, see less detail by doing this though.....sorry.

Gordon

[Mr A]

projector is a barcodata 801s if it is still available???, I know HTPC would be better or a scaler or Iscan but funds wont permit plus the player cost good money and the WAF would be low if I wanted to spend even more.

The research seems never ending. I would love to see one of these in action does anyone around Northwich have a CRT proj I can see.

I am still undecided about the event although WAF seemed ok on that one. I would have to be home on Sunday night as work is a must on the Monday!!

[Gordon @ Convergent AV]

OK Mr A,

To not see picture structure you are definately going to have to sit further awya than beside/underneath the 801. However, never fear. Just sit where you like and enjoy the pics. Then, when she complains about it say it's not a problem you know how to fix it.....and buy an Iscan or Quadscan.....

Seriously, when I was using the 800 in those pics I posted my other half only commented on the lines a few times (then again, she only watched it a few times...) and we were sitting either side of the thing!

Hope you get hold of the 801...all the best,

Gordon

[RichardA]

I actually have a formula here somewhere that can give an scientific indictaion of minimum viewing distance - What I will try and do is turn it into a set of guidlines by technology (CRT, LCD etc..) and resolution and have it ready for Gordon's EVENT - we can then give it a 'road test' to see how it works in practice before publishing it here.

Now all I have to do is find the time with the other new jobs I'm doing!

Richard

[Gordon @ Convergent AV]

Richard,

Top man!

Gordon

[squid]

as has been said . you should be a minimum of around 1.5 time the width of the screen away . this is around the same dist that you place a crt pj from screen .

if you take a look at a lot of installs you will soon notice that more often than not the first seating position is just under the pj .

i personaly sit 9feet from a 6 1/2 feet wide screen and am quite happy . i would love for a better source than dvd to come along though . somtimes the blocking gets so it is almost as bad as a good quality sky broudcast on my 32 incher :D :D :D

[Chris Frost]

Steve,
For a 2mtr wide image you can put your projector anywhere from 3.90 to 4.26 mtrs back from the screen. The seating distance you quote (3.5 to 4 metres) is about right for that product.

Using the iScan with any suitable LCD projector is a great idea. iScan reduces line flicker which means you are less likely to pick up on the artifacts that highlight the LCD matrix structure (a.k.a. chicken wire/screen door).

Regards

[Gordon @ Convergent AV]

Your screen size and distance are very similar to our dem unit. I think you have a good solution.

Gordon

[Stever]

I have a similar question. I am about to buy the PLV30 along with an iscan Pro (so that I can get a 4:3 image into a 16:9 screen). My room will be about 5 metres long by 4 metres wide (sorry metric figures only). Realistically, I will have about 4.5m from lens to screen. I would like a 2m wide screen, but my maximum seating distance from screen will be around 3.5 to 4 metres. Will this be a comfortable seating distance for a 2m wide screen (would 1.8m be preferable?) and will it be far enough to lose the chicken wire effect?

Any advice would be gratefully received.

Steve

[Stever]

Chris/Gordon,

Thank you both - that was exactly the confirmation that I was after. I will now be getting the PLV30/iscan combo within the next few weeks. I'll post my comments once it is all set up.

Thanks again,

Steve

[Nick Beecham]

Hi Gordon

Is this thing about sitting further away from the screen than the projector an important rule? My room is about 22' x 11'. I hope to have an 8' wide screen with seating in the middle of the room, about 11' from the screen. I was hoping to site the projector at the back of the room, about 22' from the screen. In this way, I won't have to look at the projector while watching a film + any noise from the projector will be a reasonable distance behind me. Is this going to be a problem?

Many thanks in advance
Nick

[GarryF]

Nick, what projector were you thinking of using ? most have a fixed throw ratio determined by the width of screen. CRT for instance is approx 1.5 times screen width to the lense which would be around 12 feet in your room. Sony 10HT has a short throw distance and the seleco 200 has a long throw distance.

[Gordon @ Convergent AV]

Nick,

No it's not an important rule. Garry has already mentioned the fact that many different projectors have different throw distances....

Gordon

[Nick Beecham]

Thanks Guy

That's a relief.

Nick