Film-Tech Forum ARCHIVE: Dual Projector DLP

This is topic Dual Projector DLP in forum Film-Yak at Film-Tech Forum ARCHIVE.

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Posted by Jake Spell (Member # 5294) on 03-19-2012, 04:48 PM:

Im thinking about getting two DLP projectors for a large wall in our office and overlapping the images to get more light on the wall. Would the two projectors overlapped look odd since the color wheels are not in sync or would the sync up via HDMI. They will be running off a laptop HDMI out then through a spliter and to each projector.

Thanks! [beer]

Posted by Marcel Birgelen (Member # 6801) on 03-19-2012, 06:41 PM:

I don't know what equipment you will be using, but good luck keeping the images alligned correctly, without constant manual tweaking.

If you use exactly the same projectors, color wheel sync or LED sync will probably not your biggest enemy. I've already experimented a bit with partially overlapping images and I didn't see any weird discolorations. Of course, the actual results might vary between models.

Posted by Tony Bandiera Jr (Member # 2365) on 03-19-2012, 06:43 PM:

As a guess, I would say that since they are going to be rendering the same image and colors at the same time the color wheels would be in sync by virtue of rendering the same image.

If you already have the two projectors just do it and let us know how it turns out. [thumbsup]

Posted by Jake Spell (Member # 5294) on 03-19-2012, 08:45 PM:

Im not against tweaking them all the time, Im used to it from working with whatever's laying around. Of course for once these will be matched Acer P7500 1080P 4klumen projectors. Iv got a feeling it wont be too much of an issue but I wanted to aske the experts first!
[thumbsup]

Posted by Randy Stankey (Member # 64) on 03-20-2012, 07:51 AM:

I have to say that I don't much care for single chip, color wheel style projectors. No matter how good they claim to be, you can always see color fringing on fast action scenes and any time when something moves in front of the screen. (e.g. When somebody walks in front of you to sit down.) In fact, I can see fringing when I merely blink my eyes.

I personally find color wheel type projectors to be annoying to look at. A lot of other people I know also find them annoying but, because they don't understand what the problem is, they don't know why. They just get fidgety and have bad moods. It's like when your 35mm projector gets a case of the jitters and half your audience walks out of the theater with a headache.

I suggest you dump the color wheel projectors and get better equipment. Then the question of syncing them up will be moot.

Posted by Jake Spell (Member # 5294) on 03-20-2012, 08:36 AM:

I agree with you Randy, I dont like them much either but unfortunately there's not enough money for 3chip DLP

Posted by Randy Stankey (Member # 64) on 03-20-2012, 10:31 AM:

Why don't you just spend twice as much on one projector and get twice the bang for your buck?

A 4K projector puts out a decently bright picture for office/board room use. Unless you want to be able to see the picture in full room light or unless you have a really big wall to cover, that ought to be enough light. I used to cover a 12 foot tall screen with a 3K projector. It was dim in room light but it was acceptable with the lights out. Yes, we were under gunned but it worked. I can't imagine how a projector that's brighter and shooting on a smaller screen could produce a lower quality picture.

Instead of spending $1,800 apiece on two projectors, why not spend $3,600 on one projector. You'll probably get a better picture and you won't have to fuck around getting them lined up and you won't have to continuously fuck around with them to keep them lined up.

Not to mention the fact that you will only have one lamp to replace and one projector to repair when it malfunctions. (Not IF it malfunctions. WHEN it malfunctions. You should always assume that every piece of technology WILL malfunction and plan for it from the start. As they say, "Plan for the worst but hope for the best.")

I'm not saying that multiple projector setups are bad. Places do it all the time. The Met Opera does it for their stage performances and it looks really good. On the other hand, they have people who get paid thousands of dollars for EACH PERFORMANCE to make those projectors work and to keep them working. You, on the other hand, are one guy who gets paid peanuts to do the job of two people. The people around you are proverbial idiots and, when problems occur, they will be looking to YOU to come solve all their problems.

Why not just save yourself all those headaches and all that trouble right now? Spend more money on one projector and be done with it.

Posted by Marcel Birgelen (Member # 6801) on 03-21-2012, 08:19 AM:

I agree with Randy that a single projector solution will probably get you into the least amount of headaches and it can probably also done for the same budget.

Although, the dual projector setup has one real advantage: redundancy, if one lamp or projector fails, you still have picture, although with highly reduced brightness.

I also hate color wheels, but the more recent models have improved them by adding more colors or more of the same colors, so the rainbow effect isn't as noticable as before.
Additonally, the new LED based DLP projectors do not use a color wheel, so the refresh rate is not limited by the speed of the color wheel and the rainbow effect seems to be gone entirely.

It will be interesting to see if future D-Cinema equipment based on laser technology will be using single or 3 chip solutions.

Posted by Dominic Espinosa (Member # 2122) on 03-21-2012, 03:34 PM:

quote: Randy Stankey
Instead of spending $1,800 apiece on two projectors, why not spend $3,600 on one projector. You'll probably get a better picture and you won't have to fuck around getting them lined up and you won't have to continuously fuck around with them to keep them lined up.

I was beginning to wonder why that wasn't suggested...

I don't know what you're using these things for but if you stay further out of the DCinema arena and get something like a Panasonic in the PT-DW family you'll get a redundant bulb system. It'll do exactly what you'd expect. Use one only and have the other as backup and a dim image OR if one fails the other continues to run.

Otherwise all I can say is I hope this isn't for a screening room is.

Posted by Jake Spell (Member # 5294) on 03-22-2012, 12:42 AM:

Its for a software/website company that moved in next to us. Im doing this as a little hobby with the guy that owns the company.

The main reason that I want two is redundancy. Have two lamps in one projector is one thing but two separate projectors, to me, is the more redundant system of all. Also from everywhere Iv looked to just up to a brighter lamp/dual lamp setup brings about $4,000 increase in price but that could be simply that Im looking in all the wrong places...

The other reason is that it must have 1920x1080 resolution so they can check the sites for errors.

Posted by Randy Stankey (Member # 64) on 03-22-2012, 10:18 AM:

Definitely do what you think is best and definitely consider what the customer wants. No doubt there.

However, when making your cost analysis, consider the wiring, mounting and infrastructure needed to support a second projector.

You need a good, solid mounting bracket. Don't let them suspend it from a drop ceiling! Connect it to a steel beam. I would never allow somebody to do anything less. Depending on the structure of the building, you could get away for a few bucks or it could cost $100.

There's an extra set of signal cables, power and control cables. Depending on the length of the run, that could add up. Easily $50.

What about the HDMI splitter? How much does that cost? (I don't know exactly. I'm only pointing it out.)

I'm just saying that the cost of the second projector is not the only cost you have to bear. Also, don't forget maintenance. There's a hidden cost in keeping the projector clean and working well. This does not consider that you now have to keep two spare lamps on hand instead of just one.

Finally, if there ever comes a time when one of those projectors is removed in favor of just one, all the expense of installing the second becomes a "sunk cost." (Money that's basically thrown away.)

If there really is a need for two projectors, I'm all for it.
Do what you think is best and do what the customer wants.

However, unless there is some overriding need, I still think the money would be better spent on buying one, bigger, better projector.

Posted by Dominic Espinosa (Member # 2122) on 03-22-2012, 01:29 PM:

Splitter is maybe 20-40 bucks.

Of course if you're not the one doing the wiring it's going to go way up for that persons labor.

If you factor in power consumption and all that nonsense it's only slightly cheaper installing 2 smaller projectors than 1 big one.
Sony makes one you can get retail for under $8k, can take everything, and puts out 7000 lumens.
A much cheaper alternative to a Panasonic.

Posted by Randy Stankey (Member # 64) on 03-22-2012, 02:00 PM:

Appeal to their "man cave" instinct! [Big Grin]

Seven THOUSAND lumens! MORE POWER!!