best projector electric screen image
Abdou arra
Yep, im designing a home theater and I need to know everything, from speaker placement to why should I get it really? EVERYTHING YOU KNOW.
Answer
There are really a lot of considerations to think about. I would start by looking at examples of what others have done. The AVS forum is the place for that... http://www.avsforum.com/avs-vb/forumdisplay.php?s=&daysprune=&f=19
I'll list a few things and leave it to you to do some research...
1. Consider doing a "CIH" system, that is Constant Image Height. For this you need a 2.4:1 or greater aspect screen, video scaling, and an anamorphic lens. I like Prismasonic lenses because they are adjustable. http://www.prismasonic.com/account/order_form.php Movie aspect ratios vary quite a bit so this lens allows you to adjust for this.
2. Consider a curved screen. This can correct for distortions in the lens and can improve brightness uniformity just a little by slightly reducing the maximum off axis viewing angle. Btw, you can build your own screen relatively easily using DaLite material from http://store.cousinsvideo.com/cut-to-size.html
3. Draw the layout of your room, from that determine viewing distances, off axis angles etc. You will need to know all these things for choosing a projector, screen material etc. I used a 1.3 gain material, it's a good solution for most typical dedicated home theatre applications but you need your room drawing to determine if it's right for you.
4. Think about equipment location. You may want to build a control closet attached to the room.
5. Paint the ceiling flat black, you won't be sorry. Also a neutral gray is good for the walls but it needs to be very flat. Also don't hang glass covered movie posters on the walls in your theatre, these belong outside in your theater lobby area.
6. You can use a Receiver if you go with a high end one but I would suggest using external amplification for the main LCR channels. A lot of people argue this isn't necessary but I've always found it to sound better. Your best approach is not to use a receiver but a preamp processor. The advantage of the receiver is that it eliminates the need for external amplification of the surround channels. Usually the receivers built in amps are good enough for surrounds so it's a convenient package to have all that built in. It is still a compromise over going with a preamp processor however.
7. I don't know what to tell you on speakers. I've been building my own since the mid 1970's, actually early mid 1960's if you count mounting old TV speakers in card board boxes when I was about 6 years old. After so many years experience and the good fortune of influence by many speaker designers far smarter than me, I simply can't get excited about any of the commercially available speaker systems out there. I can only say don't go too small. If a speaker is operating in a range where it becomes stressed at typical play levels then it's not going to perform very well. Get something capable of far more output than you need and then at least it will have a more "effortless" or "easy of delivery" sound. Some people use commercial cinema speakers in their home theatre. While these don't produce the most refined or musical sound in my opinion they can certainly be a lot better than a lot of the mass market non sense out there.
When I was developing my theatre I did a lot of googling. I would just type in "Home Theatre" and click "Images" or sometimes just a normal web search. I looked at every example I could find! I had never head of an anamorphic lens before at that time. Before any ground was broken for the house the theater evolved from a combination game room/theatre with a 100" 16:9 screen to a totally dedicated theatre with stadium seating using Berkline electric recliners, a 144" 2.4:1 42' radius curved screen with anamorphic lens... So google away and find every example you can!
Edit: Grumpy Mac, I think you have Abdou wrong. His previous questions do not suggest he is a troll. His answers are short an to the point... too short in fact usually 2 or 3 words. I think just not a man of many words! Abdou, it really would help if you told us more of your plans. Of course when I started dreaming up my system I could not place a fixed budget on it. I didn't know enough about what I wanted to know what budget to put on it. I ended up spending almost $50K and I'm still going.
If I had put that number on it up front I wouldn't have let myself start. So I can understand if you don't know what budget to place on it but we really do need to know at least some idea. Also not just budget but more about room size plans, dedicated room or not... etc etc etc...
mk
There are really a lot of considerations to think about. I would start by looking at examples of what others have done. The AVS forum is the place for that... http://www.avsforum.com/avs-vb/forumdisplay.php?s=&daysprune=&f=19
I'll list a few things and leave it to you to do some research...
1. Consider doing a "CIH" system, that is Constant Image Height. For this you need a 2.4:1 or greater aspect screen, video scaling, and an anamorphic lens. I like Prismasonic lenses because they are adjustable. http://www.prismasonic.com/account/order_form.php Movie aspect ratios vary quite a bit so this lens allows you to adjust for this.
2. Consider a curved screen. This can correct for distortions in the lens and can improve brightness uniformity just a little by slightly reducing the maximum off axis viewing angle. Btw, you can build your own screen relatively easily using DaLite material from http://store.cousinsvideo.com/cut-to-size.html
3. Draw the layout of your room, from that determine viewing distances, off axis angles etc. You will need to know all these things for choosing a projector, screen material etc. I used a 1.3 gain material, it's a good solution for most typical dedicated home theatre applications but you need your room drawing to determine if it's right for you.
4. Think about equipment location. You may want to build a control closet attached to the room.
5. Paint the ceiling flat black, you won't be sorry. Also a neutral gray is good for the walls but it needs to be very flat. Also don't hang glass covered movie posters on the walls in your theatre, these belong outside in your theater lobby area.
6. You can use a Receiver if you go with a high end one but I would suggest using external amplification for the main LCR channels. A lot of people argue this isn't necessary but I've always found it to sound better. Your best approach is not to use a receiver but a preamp processor. The advantage of the receiver is that it eliminates the need for external amplification of the surround channels. Usually the receivers built in amps are good enough for surrounds so it's a convenient package to have all that built in. It is still a compromise over going with a preamp processor however.
7. I don't know what to tell you on speakers. I've been building my own since the mid 1970's, actually early mid 1960's if you count mounting old TV speakers in card board boxes when I was about 6 years old. After so many years experience and the good fortune of influence by many speaker designers far smarter than me, I simply can't get excited about any of the commercially available speaker systems out there. I can only say don't go too small. If a speaker is operating in a range where it becomes stressed at typical play levels then it's not going to perform very well. Get something capable of far more output than you need and then at least it will have a more "effortless" or "easy of delivery" sound. Some people use commercial cinema speakers in their home theatre. While these don't produce the most refined or musical sound in my opinion they can certainly be a lot better than a lot of the mass market non sense out there.
When I was developing my theatre I did a lot of googling. I would just type in "Home Theatre" and click "Images" or sometimes just a normal web search. I looked at every example I could find! I had never head of an anamorphic lens before at that time. Before any ground was broken for the house the theater evolved from a combination game room/theatre with a 100" 16:9 screen to a totally dedicated theatre with stadium seating using Berkline electric recliners, a 144" 2.4:1 42' radius curved screen with anamorphic lens... So google away and find every example you can!
Edit: Grumpy Mac, I think you have Abdou wrong. His previous questions do not suggest he is a troll. His answers are short an to the point... too short in fact usually 2 or 3 words. I think just not a man of many words! Abdou, it really would help if you told us more of your plans. Of course when I started dreaming up my system I could not place a fixed budget on it. I didn't know enough about what I wanted to know what budget to put on it. I ended up spending almost $50K and I'm still going.
If I had put that number on it up front I wouldn't have let myself start. So I can understand if you don't know what budget to place on it but we really do need to know at least some idea. Also not just budget but more about room size plans, dedicated room or not... etc etc etc...
mk
How does this 3D Glasses mirror trick work?
Mike S
Using one of those RealD glasses from the movie theaters look into a mirror while wearing them. Then alternating closing one eye than another. The side of the open eye will be black and you can't see your eye in the reflection, while the side of the closed eye will be clear and you can see your closed eye in the reflection. (Oddly, even though you can't see your open eye - as it appears black in the reflection - you can see through the "black" lens to see your closed eye in the reflection)
How does that work?
Thanks!
Answer
To understand this, you need to know a bit about light polarizers, as that is what those glasses are. So, very briefly, the are multiple types of polarization. The most common types are vertical and horizontal polarized light, which means the electric portion of the wave is oscillating in the vertical or horizontal direction. A polarizer is a piece of glass or plastic that has tiny parallel lines on it (or at least something that acts as tiny parallel lines) and these lines only allow light that is aligned with the lines to pass. So a vertical polarizer will have vertical lines, and it will let light that is vertically polarized pass, while it will block horizontally polarized light. If you rotate that polarizer by 90 degrees, so that the lines are horizontal, it will become a horizontal polarizer.
Now there are also two types of diagonal polarization, where the electric field oscillates in either the +45 or -45 degree. As it turns out, +45 degree light is just vertical + horizontal light, and -45 degree light is just vertical - horizontal. So both of these diagonal polarizations will pass through the vertical or horizontal polarizers, but will lose half their intensity when doing so, because the polarizer will block half that light.
Now, here's the tricky part. There is also circular polarized light. Circular polarized light is a lot like diagonal light, except that the phase of the vertical and horizontal components is not the same. So it looks like the e-field is spinning. There are two types of circular light, left-handed and right-handed polarizations, where one spins one way and the other spins the other way. Like diagonal light, half of circular-polarized light will pass through a vertical or a horizontal polarizer.
These 3D glasses work using circular polarizers. So one eye-piece has a left-handed polarizer, the other has a right-handed polarizer. When you look at yourself in the mirror, you are looking at light that hits your face, bounces off to the mirror, reflects from the mirror, and goes into your eye. When you have these glasses on, it changes a bit. Now the light hits your open eye, bounces off that towards the mirror. But before it hits the mirror, it must pass through the circular polarizer. That light, before the polarizer is an equal mixture of left and right circular light. But only the right circular will pass through the lens. So the light that hits the mirror is 100% right circular light. When it hits the mirror, a mirror will turn right-circular into left-circular (it's just what mirrors do). Then this light will come back to your eyes. But now the light coming from your open eye is left-circular and it gets 100% blocked by the right-circular polarizer in front of your open eye. On the other hand, light that started near your closed eye will pass through a left-circular polarizer and will hit the mirror, become right-circular, and will come back to your open eye, where it will pass that lens and enter your open eye. So the mirror acts to flip the circular polarization of the light and allows the light from your closed eye to be seen but not the light from your open eye.
The 3D movie uses this as well. It uses fancy projectors that project a left-circular image for one eye and a right-circular image for the other, giving two different images for you two different eyes. When your brain puts the two images together, it makes a 3D image out of it.
Now, I would like to point out that there aren't any good circular polarizers in real life. So the lenses in your 3D glasses aren't real circular polarizers. What they actually are is a quarter-wave plate, which rotates the polarization of light from circular to linear, and then a horizontal or vertical polarizer on the side of the lens closer to your eye. These two components behaves the same way as a circular polarizer would for light coming one way (from the screen to your eye), but differently for light going the other way (from your eye to the screen). So if you turn those glasses backwards, you will not get the same results for your little experiment.
To understand this, you need to know a bit about light polarizers, as that is what those glasses are. So, very briefly, the are multiple types of polarization. The most common types are vertical and horizontal polarized light, which means the electric portion of the wave is oscillating in the vertical or horizontal direction. A polarizer is a piece of glass or plastic that has tiny parallel lines on it (or at least something that acts as tiny parallel lines) and these lines only allow light that is aligned with the lines to pass. So a vertical polarizer will have vertical lines, and it will let light that is vertically polarized pass, while it will block horizontally polarized light. If you rotate that polarizer by 90 degrees, so that the lines are horizontal, it will become a horizontal polarizer.
Now there are also two types of diagonal polarization, where the electric field oscillates in either the +45 or -45 degree. As it turns out, +45 degree light is just vertical + horizontal light, and -45 degree light is just vertical - horizontal. So both of these diagonal polarizations will pass through the vertical or horizontal polarizers, but will lose half their intensity when doing so, because the polarizer will block half that light.
Now, here's the tricky part. There is also circular polarized light. Circular polarized light is a lot like diagonal light, except that the phase of the vertical and horizontal components is not the same. So it looks like the e-field is spinning. There are two types of circular light, left-handed and right-handed polarizations, where one spins one way and the other spins the other way. Like diagonal light, half of circular-polarized light will pass through a vertical or a horizontal polarizer.
These 3D glasses work using circular polarizers. So one eye-piece has a left-handed polarizer, the other has a right-handed polarizer. When you look at yourself in the mirror, you are looking at light that hits your face, bounces off to the mirror, reflects from the mirror, and goes into your eye. When you have these glasses on, it changes a bit. Now the light hits your open eye, bounces off that towards the mirror. But before it hits the mirror, it must pass through the circular polarizer. That light, before the polarizer is an equal mixture of left and right circular light. But only the right circular will pass through the lens. So the light that hits the mirror is 100% right circular light. When it hits the mirror, a mirror will turn right-circular into left-circular (it's just what mirrors do). Then this light will come back to your eyes. But now the light coming from your open eye is left-circular and it gets 100% blocked by the right-circular polarizer in front of your open eye. On the other hand, light that started near your closed eye will pass through a left-circular polarizer and will hit the mirror, become right-circular, and will come back to your open eye, where it will pass that lens and enter your open eye. So the mirror acts to flip the circular polarization of the light and allows the light from your closed eye to be seen but not the light from your open eye.
The 3D movie uses this as well. It uses fancy projectors that project a left-circular image for one eye and a right-circular image for the other, giving two different images for you two different eyes. When your brain puts the two images together, it makes a 3D image out of it.
Now, I would like to point out that there aren't any good circular polarizers in real life. So the lenses in your 3D glasses aren't real circular polarizers. What they actually are is a quarter-wave plate, which rotates the polarization of light from circular to linear, and then a horizontal or vertical polarizer on the side of the lens closer to your eye. These two components behaves the same way as a circular polarizer would for light coming one way (from the screen to your eye), but differently for light going the other way (from your eye to the screen). So if you turn those glasses backwards, you will not get the same results for your little experiment.
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Title Post: Anything you know about home theater surround sound?
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Rating: 100% based on 99998 ratings. 5 user reviews.
Author: Unknown
Thank FOr Coming TO My Blog
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