Was curious if i could use mirrors on the inside of my box in the light tunnel to increase brightness. or even move my light farther back from the lcd sled area. if anyone has insight on this please let me know thanks.

It will not work. You can only use the light from a point source.

To expand on that...

We're only interested in light that we can get to the triplet. The fresnel lenses do that because the light comes from one source, so we can direct it to one destination. The mirrors represent light that coemes from another source, and as such are not directable. The object isn't to get more light through the LCD, it's to get more light throught he LCD to the triplet. This is an important distinction. Unless you can direct the light off the mirrors to the triplet, it's all a waste.

As to moving the light back, the problem with this is inverse square law. If you mive the light to twice the distance from the panel, you only get a quarter of the light intensity. So if you were to replace the 220mm collimating fresnel with a 440mm fresnel, you'd get only 25% of the projected lumens.

Similarly, if you could use a 110mm fresnel, you could get 4 times the projected lumens. The problem there is vignetting. There's an entry in the FAQ about this, regarding inverse square law.

Basically though the idea doesn't work. If you could generate a collimated stream of light, the story becomes different than just a light tunnel.

While I can't add to the explanation given above, I thought I'd pass this along:

Below is a little information that I like to pass along to new members:

The best place to start is The Lumenlab PRO DIY Projector Guide V.3.

Once you have a grasp of the basics, you might want to peruse the pinned topics at the top of the Beginner's Forum. This is also where you should go to create your own threads when you have questions.

Then you can move on to the pinned topics of the DIY Video Projector Design forum and the FAQ section.

When you're ready, you'll need to decide what parts (LCD, Fresnels and triplet) you'll need. To do that, you can use the handy FocalCalc. FocalCalc will help you determine your enclosure measurements and will let you experiment with different parts before buying anything. This will also tell you how far from the screen your projector needs to be (throw distance).

When you start your build, you can create your own PLOG (Projector Log) to chart your progress and to ask questions about your particular build.

I've found that Google Sketchup is handy to use to design and visualize what your projector will look like. And best of all, there's a free version you can use. If you go to the Google 3D Warehouse and do a search for Lumenlab, you'll find that some members have uploaded parts that they have modeled so you can download them and use them in your own model.

A lot of the questions you might have probably have already been asked and answered several times. While most of us do not mind answering some of the same questions repeatedly, you might get more satisfaction in finding the answers yourself. Unfortunately, the built-in Search feature on most of these online forums is quite limited in what it can do. You might find it easier to search using Google using the "site" parameter. Below is an example:

Google search: site:lumenlab.com "light tunnel"

You can find other parameters by clicking the Google links in my signature.

You might run across a "quirk" when searching using Google, however. If you notice the thread looking "wonky" like this image, simply go up the the top right corner of the thread and click on Options and then Switch to: Standard.

I hope this gets you started on the road to your new obsession and I look forward to seeing your progress.

edit/
I just noticed that you've been a member since 11-March 07. I hope the above did not offend.

Thanks to you guys for answering me, shortly after that post i realized it would not work. I have been on this site since 07 but ive been lazy about getting it all done, this last 2 weeks i have been putting some time into it and i have a good vertical type box built that does project nicely and focused, good enough for my needs at this point, but im using a 400 watt Metal Halide and cartoon movies like disney show up very well, but when it comes to a human movie and some dark scenes its not the greatest, im wondering what would be the best light in my case. basically im wondering if the standard light sold on lumenlab would be brighter then my 400 watt metal halide?

thx in advance

The LL light itself is a nice lamp, but it's still a 400W MH lamp, and will be about the same brightness. The reflector helps signifigantly as well. You shoud also pay attention to your brightness and contrast controls on your LCD. I find that default settings are generally good for what I want.

What make and model of lamp are you currently using?

There's always the Best Bulbs Chart.

Not sure of the make and model of my light, i beilieve it says VENTURE on the bulb somewhere. i actually did a mock up with my box to verify the throw distance, brightness and focus tonight out in the garage, even though i had brown 8' sheets of mdf for my screen, i was really impressed. i dont even have a parabolic reflector yet. but the brightness i achieved is far good enough for the purpose of my projector, which is just to be used for movies at night in th eliving room, although i am going to play some counter strike on it for sure!