A hot sealed inflatable screen is recommended for backyard and indoor use such as halls or gyms where the blower noise will be more noticeable. All screens sold by Smart Digital Australia with an image width of 4 metres are more compact and easier to handle they also feature a constant air option that keeps your inflatable screen inflated without the noise because typically the blower is placed behind the screen and the audience is normally about 5 metres from the front of the screen. Should there be any residual blower noise it becomes instantly a non-event as soon as the film soundtrack commences.
Secrets Behind Screen Surfaces
Three types of screen surfaces are available today; one for projection on the front of the screen, one for projecting from the rear of the screen and lastly a screen surface that will do both front and rear projection. On Smart Digital’s HandiTheatre® and ParkView® outdoor inflatable movie screens, a special theatrical quality stretch Lycra white surface is used that allows for either front or rear projection. This is for movie screens up to 6 metres wide net picture area (NPA).
On our larger Touring® screens (up to 12 metres wide) and the SmartFold® indoor screen, either a front or a rear projection surface must be specified because the Touring® screen is a much bigger movie screen and thus a very lightweight stretch Lycra fabric is not suitable for such a huge screen surface. The SmartFold® screen surface is press studded to its frame and utilizes special theatrical PVC screen surfaces.
The special screen surfaces used on both the Touring® screens and the SmartFold® are either white for front projection or a grey surface for rear projection. The white surface is a “solid” surface so there is no projector lamp. If the lamp was visible to the audience it would be uncomfortable and shine a relentless light into your eyes. The grey surface also assists with brightness and more clarity of the projected image in challenging ambient light conditions.
How to Achieve Rear Projection
The key to understanding rear projection is to remember that the image from the projector must be reversed. This is relatively easy and most modern projectors have a “settings” function just like a PC. To set the projector to rear projection go into settings and “flip” the image. From the rear, the image on the screen will be reversed and on the front where the audience is located the image will appear to be normal.
Front vs. Rear Projection
For the majority of audiences determining whether to use rear or front projection is a minimal decision. For larger audiences or audiences consisting primarily of many children rear projection is preferred because most of the projection equipment will be located behind the screen and out of the way and thus it is less likely for someone to be caught walking in front of the projector.
Projector Lens Types Unveiled
There are three main types of projection lens available short throw, normal and tele lens. The versatility of changing lenses is only compatible with more powerful projectors. Standard low cost projectors typically use normal lenses. Slightly more expensive projector models are available with a short throw lens – which is an advantage if space is limited because a larger image can be produced with the projector sitting closer than normal to the screen.
Normal throw lenses are included with most consumer and commercial projectors and are typically affordable and offer excellent image display with a lens to screen distance between 5 and 15 metres (depending on the dimensions of the screen). A short throw lens will reduce this “throw” by about two thirds. For example, a lens with a throw of approximately 15 metres will be reduced to about 5 metres. A lens with a long throw will enable the projector to be placed at the rear of the audience with front projection similar to normal hardtop cinema screens. In the outdoor movie business a long throw or “tele” lens is rarely used.
Short throw lens projection reduces the distance between the lens and the screen which will result in a marginally brighter image on the movie screen. This technique will also enhance a screen image when ambient light proves to be challenging. The other advantage is that it reduces the real estate required to screen an image. When space is limited this can be very advantageous.
Simple Yet Balanced Sound
The powered audio speakers are usually placed on either side of the inflatable screen. If two or more pairs of speakers are used the place speakers reasonably close to each other side by side on either side of the screen. It is a good idea to place the speakers about 5 metres apart and close to the front of the movie screen. The speakers can be daisy chained so that one XLR speaker cable will come out the left or right side of the SmartBox® and be connected to the first speaker. Then connect another XLR lead to the OUT of the speaker and connect it to the next speaker by its side. Repeat the procedure for the other channel. Multiple speakers should be all placed near the front of the audience rather than down the sides of the audience. This will give a more comfortable sound and reduce audio delay.
A sub-woofer will enhance the quality of the sound particularly where there is a reasonable amount of music on the sound track. The sub-woofer should be placed on the ground at the front of the screen and daisy chained from one of the speakers as mentioned above.
Latest posts by James Cunningham (see all)
- Open Air Cinema Guide: How to Generate Revenue with Outdoor Movies - November 16, 2017
- Open Air Cinema Guide: How to Set Up the Movie System - November 16, 2017
- Open Air Cinema Guide: How to Prepare a Movie Night - November 15, 2017