Projecting Sight and Sound
The first aspect was the projectors. When using dual projectors it is best if the two projectors can be
identical. Unfortunately as we were using projectors borrowed from different sources this was not
possible. The biggest impact this had was that keystone correction worked differently giving a different
aspect ratio on the two screens. This was partly because we needed to set the keystone correction on
it's highest setting.
Positioning The Projector
One problem that I have experienced constantly is the issue of having to angle projectors at a steep angle.
Most projectors are designed to be used so that the projected image is only a few degrees higher
than the projector. This works OK in an office environment where a desk or stand is used. However for
the stage (and also applicable to large conferences) it is beneficial to raise the height of the
projected image, perhaps at a 45° angle. In the past I have used books, boxes, lever arch files and
all manner of different items to achieve this. For this show I decided to create my own adjustable
stand. This was created using 2 pieces of laminated wood that are hinged together. The top piece had rails
fitted (using cupboard door handles) to hold the projector in place. To make the height adjustable
wooden blocks were created with wooden dowels to hold them together. By using one, two, or three blocks
of wood the angle could be adjusted. Fine adjustments can still be made using the feet of the projector.
The projector stand could be placed on top of a table or stool to raise the angle of the projector.
Screen
For the show we wanted to create a screen that didn't use stand. We used a very thick white sheet cut
to the appropriate size. We would have liked to mount that on a wooden frame and fasten it to the wall
however drilling into the side of the stage was not an option. Instead we had to use white "Gaffa" tape.
Unfortunately the wall was artexed which made it harder but with enough layers of tape it managed to
stay up for the duration of the show.
The Image on the left shows the screen and the projector on it's stand. As you can see the screen is significantly
higher than the projector, and this needed the steep angle.
Sound
Most of the output from the laptop didn't require sound. However we did include some video with sound as
a filler between some of the sketches. This sound needed to be fed into the theatre sound equipment.
The only sound output available on the laptop used for the projection is a standard stereo headphone socket.
Although we tried using a splitter adapter that we use in conjunction with the projector this was not really
suitable. Therefore a USB external sound module was used. The equipment used was a EDIROL UA-25.
The image on the right shows the USB cable entering the adapter and the 2 theatre sound plugs that
connect this to the sound deck. The device took it's power from the USB and did not need an external
power supply.
Autocue Screens
There were a lot of songs that had to be learned in a short period of time. Allowing for the different age
groups that were expected to remember these we decided to provide an autocue. Performers were still encouraged
to learn the words, but if they were stuck on stage they were able to look at the autocue.
The autocue consisted of two flat screen monitors positioned at the front of the stage about a third of
the way from each side. These were placed on chairs and a black cloth draped over to hide them from the
audience. The image below shows the screens with highlighting so that you can see them. By looking at the earlier
picture you can see what the audience could see.
Computer Desk
The image below shows the computer desk used to control the main projectors and the autocue. The laptop on the
left ran the autocue, and the one on the right the projectors. On the show nights there were two operators, one
for each laptop, but during the rehearsals and dress / technical rehearsals this was done by a single operator.
Whilst it was possible for one person to control both, as they both needed changes at the same time it was
easier with two people.
The desk was positioned to the right hand side of the stage between the band and the conductor. The operators
could see the projected images, and the stage to ensure that they were always projecting correctly. With
access through a door to the rear of the stage which provided access to the distant projector in the event that
there was a problem with the projector. Fortunately this was not needed.
Video Cables and Splitter
To run two projectors (monitors for the autocue), from a single VGA output port required VGA splitters.
These are available as passive devices, if the cable was relatively short, but for the long cable runs required
we had two active port splitters. One was a 4 device and the other a 8 device splitter, sending the same input
to a maximum of 4 and 8 projectors / monitors. As these were active devices that retransmitted the signal these
could theoretically double the maximum cable length by positioning the splitter at the midway point.
The splitter was placed under the stage extension so was hidden from site and as a result required less
cables to be run from the laptops to the stage. The splitters did require their own power supply, but this was
provided by using multi-way adapters on the electrical feed used for the projectors.
When transmitting VGA signals over long distances then you have to be careful that the signal doesn't
deteriorate. If the cable length is 15 meters or less then you will pretty much get a good signal at the
far end, but going much further and the signal may suffer from shadows, or blurred images, or eventually
drop off all together. Generally it's considered that you can go up to 30 meters using a good quality cable,
but this may depend upon the resolution being used, and any noise from nearby power cables etc. The use of
an active splitter can effectively double the maximum length by having a second cable between the splitter
and the projector, but that also depends upon having somewhere convenient that the splitter can go with an
appropriate power source.
The splitter in use required a Male-to-Female cable to connect between the laptop and the splitter, anda
Male-to-Male cable to connect from the splitter to the projector. I used 15 m cables from the laptops to the
splitters (this was more than was needed but was purchased to allow for excess depending upon where the projectors
were located), and then a 5 m cable from each of the splitters to the nearest projector / monitor and a 15 m
cable from the splitter to the distant projector / monitor. These lengths were more than adequate for the size
and position of the stage.
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