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Frequently Asked Questions - Home Cinema

FAQs - Home Cinema

Screen burn is where a ghost image of a channel logo is left on the screen once the set has been turned off or onto another channel. The problem doesn't affect LCD TVs but plasma and old fashioned CRT TVs are susceptible.

However, broadcasters have toned down the brightness of their logos and the latest plasma TVs boast screen cleaning technologies to combat the problem.

In our tests, images burnt on to the screen after a day, disappeared after normal TV viewing. After leaving a channel logo on screen for a week only one plasma TV (out of six tested) suffered any permanent screen-burn.

Version 1.0 - HDMI v1.0 was the original format, released in December 2002. It took DVI's video signal format and added in the ability to carry a Dolby Digital or DTS bitstream or only two channels of PCM audio (48kHz, 24-bit). The two-channel PCM restriction worked fine for connections between cable/satellite receivers or DVD players and a stand-alone HDTV (which only supported two channels of audio) but it wouldn't be able to support the new audio formats that were slated to accompany HD optical discs (HD-DVD and Blu-ray). Adoption of HDMI v1.0 was sluggish, as DVI-HDCP had a headstart in the market. It didn't help that HDMI shares DVI's cable length restriction i.e. anything more than about 15 meters violates the specification and is likely to require either a booster or a conversion to fiber optic.

 

Version 1.1 - It was with Version 1.1 (released in May 2004) that HDMI was finally able to make a compelling argument for superceding DVI-HDCP. HDMI could now carry multichannel PCM audio (eight channels at 192kHz, 24-bit) in addition to Dolby Digital and DTS compressed bitstreams. Version 1.1 also added support for passing the bitstream data from DVD-Audio discs, which previously had to be decoded inside the player and output as six channels of analog or passed as a bitstream through IEEE-1394 (also called FireWire or iLink, a connection type that never saw widespread adoption).

 

Version 1.2 - HDMI v1.2 was adopted in August 2005 (v1.2a was adopted in December 2005 and added some testing and certification language). The only notable difference between it and v1.1 is support for a DSD (one bit audio) digital bitstream. This means that a player can now send the raw digital signal from an SACD over HDMI to a receiver or processor, eliminating the need for decoding of the DSD signal at the player.

 

Version 1.3 - The HDMI v1.3 spec has been official since Q3 2006, however it took nearly six months for the first HDMI v1.3 sources to appear (the Playstation3), and close to a full year to see the first HDMI v1.3 receivers, and we're just now starting to see announcements for HDMI v1.3 displays. The main change to HDMI with v1.3 is the video bandwidth, which increases from 165MHz to 340MHz (10.2Gbps). This change allows HDMI to carry video signals with 30-bit, 36-bit, or 48-bit color depths (previous versions were limited to 24-bit color depth).

  1. Lamp or Lamp Module? 
    A few manufacturers offer a replacement lamp and a lamp module for their projectors. A lamp module means you are buying a complete unit - this means the lamp and the housing around it. They are intended to be user-replaceable and no advanced technical knowledge is needed to replace them. If you have the option to buy a lamp only for your projector, you will need a degree of technical expertise to replace it. By buying just the lamp you do not get the 'housing' around the lamp and changing it can be a difficult job, often resulting in damage. Whilst a lamp only might be slightly less expensive, we highly recommend you purchase a lamp module if you do not already have extensive technical knowledge of projectors and/or electrical hardware.
  2. The projector image seems dimmer than usual - what does this mean?
    It may be time to replace your projector lamp. With metal halide (high pressure mercury) lamps, you'll notice a dimming of the image brightness as the lamp loses power. Some projectors allow you to check the number of hours your lamp has been used through the built-in menu system. Check your user guide for information about this feature.
  3. How many hours will my projector lamp work?
    Just like any light bulb you would use for another purpose, projector bulbs have an expected operating time, called lamp life. This value is expressed in number of hours - typically 1000 to 2000 hours. Newer models are claiming 4000 hours of lamp life and more. The lamp's success rate is based on a bell curve, so that a majority of (but not all) lamps will meet the lamp life hours specified. Some lamps will fail sooner and this is part of the acceptable operating range of the rating.
    For projectors that are used under normal operating conditions (no more than three to five hours per day in a clean, relatively dust-free environment) the lamp will have the greatest likelihood of lasting through its entire rated lamp life. Projectors that are used more often or are exposed to environmental contaminants are more likely to show a decrease in lamp life. Projectors that are operated 24 hours a day, 7 days a week are at the highest likelihood of lamp failure before the end of the rated hours.
  4. What can I do to help my projector lamp last longer?
    • Do not allow the projector to become overheated. The number one cause of lamp failure is excessive heat. Follow the instructions in the user manual for powering down the projector to ensure that the projector has had an adequate cool-down period.
    • Operate your projector in a clean, relatively dust-free environment.
    • Clean air filters regularly.Utilize the "economy mode" if it is available with your projector model.
  5. What is the difference between a halogen and metal halide lamp?
    • Halogen bulbs last approximately 70 hours (per bulb). Metal halide lamps last approximately 1000 to 2000 hours.
    • Halogen lamps are less expensive (typically £25 - £75) than metal halide lamps (£200 - £400). The type of lamp your projector uses will be determined by the manufacturer.
    • Halogen lamps give off a yellowish image and metal halide lamps have a whiter image.
    • Halogen lamps burn at a steady rate and have a consistent brightness throughout lamp life. The brightness of metal halide lamps decreases during lamp life.
  6. What about UHP?
    UHP (Ultra High Performance) is a proprietary design of metal halide lamp manufactured by Philips that requires lower wattage for equivalent brightness. The benefits of this technology are a smaller and lighter projector, because the power supply is smaller and lighter; a cooler running, quieter, and less expensive-to-operate projector because of the lower wattage; and a longer lamp life, because the stresses on the lamp (wattage, temperature change) are reduced. UHP lamps last approximately 4000 hours whereas metal halide lamps last approximately 1000 to 2000 hours.

On average Plasma TVs use more than twice the power of 32-inch LCD screens and 2.5 times as much as conventional 32-inch widescreens. Admittedly part of that reason is their larger size (Plasma TVs tend to be 42-inches) but even similar sized LCD screens use less power than 42-inch Plasma sets.

The smaller the screen, the less power it uses. On average, a 26-inch LCD TV screen uses less than 90 watts when switched on and costs £13 a year to run. A 40-inch LCD uses almost 100 watts more power and costs twice as much to run.

The 'HD-ready' logo ensures your TV has the minimum screen resolution (1280x720) and digital sockets (either HDMI or DVI) necessary to receive and display a 720p or 1080i high definition signal.

Labels like Full HD or 1080HD usually mean the TV has a high screen resolution of 1080 lines (1920x1080). In theory this should be best for watching 1080i pictures (such as those from SKY HD) but in practice there’s more to a good picture than just screen resolution. A lot depends on the TVs digital processing software.

Such logos can also mean the TV can process a 1080p signal. However, unlike HD-ready there is no official labeling scheme and the meanings of the new logos differ between manufacturers.

It is true that, in most cases, an analog video signal displayed on an HDTV will not look as good as it would on an analog set: there are two basic reasons for this:

1. The video processing circuitry in an HDTV upscales the image, which can improve the good aspects of the image. However, at the same time, the video processing also will magnify the defective parts of the image, such as interference and video noise that is not as noticeable on a lower resolution analog set. In this case, the quality of the video processing in the TV can have either a positive or negative effect on the degree of correction for poor analog signals.

2. If you have upgraded from a 27-inch (as an example) analog television, to an large screen Plasma (lets say 42-inches) - the lower resolution analog image will degrade somewhat since you are blowing the image up to a larger size.

This is especially noticeable on VHS recordings as VHS is such a poor quality source to begin with - however, in some cases, it may not only be the TV that is a fault. If you receive your television channels over the air, it may be simply a matter of geography as to the quality of your incoming signal, however, you may be able upgrade your antenna.

In addition, if you experience poor analog reception on your HDTV and you subscribe to a cable service, switching to digital or HD cable or having the cable service come out and check your line may also help to improve the matter.

In the final analysis, take care that in 2009 (as it stands now), all broadcast signals are scheduled to go digital and the poor analog broadcast issue should be a thing of the past.

It must be noted that in some cases, when viewing theatrical films in HDTV - you may still see black bars to the top and bottom of a 16:9 image, as some films were and are made in wider ratios than 16x9.

For example: Original HDTV programming is made in the 16:9 (1.78) as aspect ratio, which fits the dimensions of HDTVs. However, many theatrically films are made in either the 1.85 or 2.35 aspect ratio, which is even wider than the 16:9 (1.78) aspect ratios of HDTVs. Thus, when viewing these films on an HDTV (if presented in their original theatrical aspect ratio) - you will see black bars on your 16:9 screen. However, the bars will be less pronounced than if the same movie was letterboxed on a standard 4:3 set.

Hollywood decided in the early stages of the DVD format, that the staggered release of movies throughout the world should be applied to this new format, for both financial and political reasons. Hence North America was designated as Region 1, Europe and Japan as Region 2 and so on ...

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Consequently they forced the manufacturers to abide by this and so a DVD player bought in the UK (region 2) will only play discs which are designated region 2, typically marked on the disc and packaging, thus ...
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The apparent result of this of course is that our friends over the pond get to watch the movies earlier, but also because Region 1 has had a 12 month headstart on region 2, the discs are of a much higher quality, cheaper and there is a far larger selection. This inconsistency fuelled the market for Multi-Region Players, players that will allow the playback of discs bought anywhere in the World, putting back the choice and control back into the consumer's hands.

We only offer multi-region DVD players

The main reason for pixelation (picture break up) on playback is contamination of the disc. Scratches, thumbprints, food, fluid and various other substances may be present on the disc and these will prevent the laser pick up from retrieving the information.

Gently wipe the surface in an outwards motion with a clean non abrasive cloth. You should remember that dvd discs are not as resilient and robust as CDs and thus should be treated with care. The second reason for pixelation will be contamination of the laser pick up.

Good practice suggests that you should really invest in a dvd lens cleaner and use this every couple of months. This will prolong the life of your dvd player and maintain  the same high quality playback as when you originally purchased the machine.

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