| mccamp82 |
I have been going through these threads like crazy the bast couple weeks, trying to get a really good knowledge on DIY projectors before I actually take the plunge and start planning my own. I have gotten a pretty good understanding of everything, and feel that I could build a great projector, but there are still a couple questions i have that I couldn't get clear answers to in the thousands of posts on this website. I will use this thread to post any question i may come up with in the next few days. Please help me out. I have been very impressed with the people on this forum and appreciate anyone's help.
Questions:
1. Do I have to mount the LCD upside down in order to get a right side up projection? FYI, I will be using a condensor, split fresnels, and the diylabs triplet.
2. If i hook up my dvd player to the xga monitor using something like the XGA Theater of Nextvision N5, will the video quality be degraded at all, or will it be a good picture? I know that it will convert the DVD to XGA, but does this blurr the image or anything? Would using a lesser resolution for s-video be better?
3. Will mounting the triplet further from the front fresnel result in a smaller picture? I am interested in making the picture a little smaller in order to posssible reduce the screen door effect. Anyone else tried this?
4. Can someone please explain the signifigance of the contrast ratio? I know the higher the first number, the better, but i don't really know what it means. Will turning the contrast all the way up on say a 500:1 monitor be clearer that one with say a 300;1 ratio? Sorry if this is a stupid question. The reason i ask is becasue i will probably be using an NEC 1545v and it only has a contrast ration of 300:1 and I want to know if this will be satisfying.
Well, i know I have more questions, but my mind has gone blank for the time being. I will post them when i think of them.
Thanks for the help.
Later |
|
|
| HouseMachine |
hi
5- simply, if you have sensitive eyes, then go for 500:1 lcd. But 300:1 would be enough for starting project imo. even, very good...
| quote: | | Will turning the contrast all the way up on say a 500:1 monitor be clearer that one with say a 300;1 ratio? |
yes you will get clear/sharp picture on your wall/curtain |
|
|
| Space Ninja |
1: Yes you have to put your lcd upside down and if you are not using a mirror you will also have to flip your lcd over (like you are looking at your lcd from the back instead of the front.)
2: Debatable but make sure to use at least the svideo. I think the best output is with a pc but I don’t think one of those boxes will be too bad.
3: Mounting the triplet further from the front fresnel will not make a smaller picture. Moving your triplet closer and further away from the front fresnel is what focuses your image. If you move it further away you will just get a blurrier picture (I guess it does actually get smaller but unwatchable). To make the picture smaller or bigger you have to move the whole projector forward or back.
4: Taken from projectorcentral.com’s dictionary
www.projectorcentral.com dictionary link
Contrast Ratio: The ratio between white and black. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. There are two methods used by the projection industry: 1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio. When comparing the contrast ratio of projectors make sure you are comparing the same type of contrast. Full On/Off contrast will always be a larger number than ANSI contrast for the same projector.
With a 500:1 projector you would have more detail in dark areas but for diyprojection I dont think 300:1 is too bad. Try playing a movie on the lcd before you take it apart. If you like the way it looks then it should be fine to put in your projector. |
|
|
| mccamp82 |
The reason I am not going to be using a PC to watch movies is because I already have a very high end surround sound system that i have the DVD player hooked up too. If I used a PC i would still have to buy a soundcard with digital outs, and right now I am not willing to spend that much money. So I will have to use what I have right now.
Thanks for the info.
Space Ninja,
Are you saying I have to turn the image over and turn it around? So it is upside down and backwards? Just want to make that clear. Thanks.
Ches |
|
|
| Space Ninja |
mccamp82 a sound card with digital out is not very expensive. It will be much cheaper than getting a line doulber (XGA Theater or Nextvision N5). Here is a link to one at new egg that is very cheap ($21 shipped) and has digital out http://www.newegg.com/app/ViewProdu...y=BROWSE&depa=0 . If you already have every thing the line doubler should not be to bad.
If you are not using a mirror after the lcd in your projector you will have to turn the lcd upside down and backwards. If you are using a mirror you only have to turn it upside down since the mirror will invert the image for you. |
|
|
| mccamp82 |
Thanks space ninja. I am just going to get a converter. As it is right now, I do not have a dvd plaer on my PC, and none of the sound cards I can find have DTS decoders. If I am not happy with the Next Vision N4, I may set up a HTPC type thing down the road. Right now you can get good deals on ebay for the N4, so hopefully I can use it and get pretty good results.
Anyone know the resolution of a DVD played through s-video? Is it like 640x480? |
|
|
| mccamp82 |
Thought of another question...
Okay, most people are using these double ended metal hallide bulbs with great results. Will the regular 250 watt bulbs work just as well? For example this one http://www.1000bulbs.com./product.php?product=548
I would like to use this in my projector due to the cost being way less than the double ended type. The ballast is also way cheaper. Will this lamp have a small enough arc length to use with a reflector and a diylabs condensor? I figure the reason most people such as CRUSER and ACE3000 use the smaller bulbs because they take up less space, but is there any other advantages to them. I really don't want to pay double for one just because it will save a little space.
Thanks |
|
|
| mccamp82 |
Clarifying a previous question...
If i hook my dvd player to my LCD panel using s-video to an XGA theater and then vga out to the monitor, will the picture quality be as good as if i had a PC with a dvd player built in? Will I have true XGA resolution? |
|
|
| mccamp82 |
| Do ballasts come with mogul sockets, or do you buy them seperately? Just want to make sure so i can go ahead and get my ballast and bulb ordered. Thanks |
|
|
| EasyPrey |
| quote: | Originally posted by mccamp82
Thought of another question...
Okay, most people are using these double ended metal hallide bulbs with great results. Will the regular 250 watt bulbs work just as well? For example this one http://www.1000bulbs.com./product.php?product=548
|
That's what I've ordered cuple days ago, heh :)
As 1000bulbs answered me - I will of course need mogul socket for it. They just sell replacement ballast/bulbs - it's supposed you have fixture with socets & wires.
Someone here said you'll probably need reflector for bulb this dim.
Anyways, if it will be ~3.5 times better than 70W MH on my prototype - I think I'll be reasonably happy. |
|
|
| Mr.Kh |
I think the main problem with the big balloon MH bulbs is that its difficult to get a reflector big enough to put in the correct placement. I use T15 bulbs (which are pricier than the round ones) and they are crazy bright - still quite large, but are fairly cost effective when you fidn them at a good price.
Here's a link to the type of bulb (at an awful price mind you - I can pick them up locally for about 60CAD and I've gotten a couple on ebay for around 20-30USD):
http://www.goodmart.com/products/243716.htm |
|
|
|
