AV Guide: Question time
Are you having some difficulty telling your LCDs from your DLPs? Brian Pipe answers your questions about buying a big screen system.
- How big a screen do I need?
Simply put, the larger the audience, the bigger the image will need to be so that viewers at the back can get a decent view. However, the same effect can be achieved by putting more, smaller displays around your room rather than just one big one.
You need to consider the intrusive nature of moving images (for example, people's heads turn to see what is on a TV even when you are talking to them), as it can really change the feel of your pub. If you are not using it most of the time consider hiding some of the technology when it's not needed.
What are my options?
The first big choice is between a flat screen display and projected images. With flat screens you can go for a plasma or liquid crystal display (LCD).
Plasma prices have fallen considerably over recent years, as have LCD prices. At the same time the performance of the technologies is being improved — both are getting larger and their ability to handle full motion video is improving.
Today, for similar sized displays, plasma is cheaper than LCD to buy but may be more expensive to own in the longer term. This is because plasma can have images burned into its surface when it has been driven hard or has displayed the same static image, such as a broadcaster's channel logo, for any length of time.
LCDs get their light from low-cost fluorescent tubes and when they wear out they can be replaced fairly inexpensively. Once a plasma screen has worn out it has to be replaced.
In the field of projection there are also choices, the first being between front or rear projection. There is no doubt that better results are achieved with rear projection, but in practice it is unlikely that anything other than a major refurb or a new build venue will be able to accommodate the set-up.
The next choice is between LCD projectors and their digital light processor (DLP) counterparts. With LCD the light is focused through a lens system onto the screen, while DLP projectors create the image with a digital micro-mirror display (DMD) chip which controls hundreds of thousands of minute mirrors, each one creating a tiny part of the image.
A new variation is the liquid crystal on silicon (LCOS) version of LCD. This is the best performer but is not without an appropriate price tag.
The best thing to do is compare the units you are considering side by side so that you can assess the contrast, uniformity and colour performance.
Television is going through an upheaval at the moment on several fronts. The analogue to digital changeover is well underway, as is the move from the conventional standard 4:3 aspect ratio to the widescreen 16:9. There are also moves to bring in new higher definition (HD) transmission to take maximum advantage of these changes.
Ask your supplier if the unit you are looking to buy is HD ready or HD compatible. Whether the additional investment is worth it will be up to you. The BBC says that by 2010 all its productions will be shot in HD.
Do I need commercial products?
In most cases the answer is yes. Consumer products are not manufactured to take the same levels of punishment that industrial products are. The equipment may be used by a changing population of staff over a period of years and has to be robust enough to cope with those that do not have a gentle touch.
Where should I position my screens?
Avoid glare from direct and ambient light which can reduce contrast dramatically — operating the screen's contrast and brightness flat out will not be as effective as re-positioning the display. It is important to ensure enough viewers have sight lines to the displays; this is where any tiered levels within the pub can be useful.
The screen and where it is placed within your pub is every bit as important as the projector. If it is done correctly the performance can be better than more expensive equipment that has been poorly installed.
How long will my new system last?
Properly looked after, your equipment will still be giving you good service at the time that you are getting tired of your regulars telling you "it's about time you got in the latest Hokey-Cokey 2500!"
In modern projectors, however, lamps and their filters need to be replaced at regular intervals and you should budget accordingly. Make sure that you know what the likely cost of replacement lamps and filters will be.
Don't underestimate how much a harsh smoky environment will impact on running costs and performance — though this may be less of a concern when the smoke ban comes into force next summer. Blocked filters can cause the lamp to overheat and blow. When this happens the unit has to be sent away for a clean and test.
The frequency you should schedule preventive maintenance visits depends on your environment and how long you have the units running. Once a year may be enough, but it could be up to four times. Ask your supplier how long lamps and filters are expected to last and check whether it can provide an emergency breakdown call-out service and handle preventative maintenance for you.
Brian Pipe is installations manager at Matrix Display Systems and chairman of the European Council of InfoComm International, the premier trade organisation for the AV industry. He can be contacted at brianpipe@matrixdsiplay.com or on 07917 437265.
