How To Choose The Best Television For You

For the last five years I have been using home-cinema projectors and a 72" fold-away screen, rather than having a big ugly TV in the lounge. My latest Panasonic projector died after just over a year, so I needed a replacement. I intended to buy a 1080p projector, but I couldn't find anything suitable for my large lounge (most have a very narrow range of zoom lens, so you are restricted about where they can be located), so I reluctantly looked at smaller normal televisions instead, with the intention of having it far closer to the sofas than the big screen.

Theoretically a plasma or LCD TV should be better than a projector in terms of most measurable criteria: contrast ratio (in normal lighting conditions); sharpness; noise; reliability; running costs etc. but to get the home-cinema effect it is difficult to beat a projector, but we were going to have to compromise.

The next decision was whether to buy a plasma or LCD TV? When the technologies were quite new the viewing angles for plasma used to be better and LCD were more reliable and used less power, but had a tendency to leave a blur behind fast moving pictures. There is little distinction between them now, but the big deciding factor for me was that there are very few (if any?) 37" plasmas available with 1080p (Full High-definition resolution) After staring at many TVs from various angles in High-Street shops, several conversations with ignorant sales staff and much research on the internet I decided it had to be a Panasonic (despite my pledge) and the basic model is the TX-37LZD80. This has all the features I need without the extra cost of extras like Freesat receiver or a 100Hz screen (which reduces flicker on very large screens) and works very well with my existing surround system.

Summary of Difference Between LCD and Plasma:

Advantages of Plasma:

Bigger screens: Screen Size from 30" to 65" or more (although LCD is catching up)

Screen Speed: Refresh rates are faster, so better for fast moving images (although the latest LCD screens are almost as fast)

Contrast Ratios: Slightly better, but again LCD has caught up

Cheaper for big screens

Colour Saturation is better

LCD Advantages:

No "Burn-in" (prolonged viewing of a static image can leave a permanent image on Plasma screens)

Thinner screen than Plasma

Viewing angle better than plasma (used to be much worse in early versions)

Power consumption lower than plasma (typically about half)

Work at high altitude (Plasmas do not)

Easier to transport (Plasmas are more fragile)

Weight: LCD are lighter and easier to mount on the wall

Longer life: Plasma TV have a shorter life (approximately half)

Higher resolution: The maximum resolution for a small screen is restricted by the minimum pixel size. Plasma TVs have small gas filled tubes, LCD can have tiny pixels

Have you ever wanted to know how to calculate what size TV you need? There are various theories about the optimum size, but it really depends on you, so the best thing to do is try viewing different size TVs at a similar viewing distance, in the shop, but I have also included the way I calculated what size to get (skip this section if you don't like maths)

The way I calculated the optimum size TV, was by considering the diffraction pattern caused by the light from each pixel on the screen, passing through the pupil of your eye. I assumed that you can resolve two pixels as independent light-sources when the peak intensity (i.e. centre) of the diffraction-pattern resulting from one pixel is coincident with the first zero (or minimum intensity) of the next one. The resulting combined intensity distribution has two peaks with a significantly reduced intensity in between - i.e. probably resolvable. It's very approximate, which is great because you can fiddle the figures to get the result you want (i.e. if you want to convince your spouse that you need a bigger TV blind them with science)

The equation that can be used to model the above assumptions is:

sin(angle of resolution) = 1.22 x (Wavelength)/(lens aperture)

Wavelength = 622 to 780 nm
lens aperture (i.e. pupil size) depends on darkness of the room, but could be anything from less than 1mm to 5mm or more

sin(angle of resolution) = 1.22 x (0.000000780)/(0.003) = 0.32mm pixel separation resolvable at a distance of 1m

so for 720p at 1m a screen 23cm high would have visible separately resolvable pixels... i.e. a 18" screen (diagonal)

or 27" for a 1080p TV at 1m

Then just multiply that screen size by the viewing distance in metres

although if you watch a blue movie (or at least a violet one with wavelength of 622) in a darker room this drops to about half the size

This calculation gives the size, above which the pixels would be individually visible.

e.g. at a viewing distance of 13 feet (4m) in a dark room you might just be able to resolve some pixels on a 36" TV and definitely on a 72" TV - If you upgraded to a 1080p TV this give a big improvement for the 72" TV but not much improvement for 40" or less (This is all very approximate and the best thing to do is have a look at some TVs in the shop at an appropriate distance)

After much procrastination and research, I finally got round to buying a new television. There are many to choose from, and a lot of manufacturers. This lens is the result of the research I did. The TV I chose was a Panasonic TX-37LZD80.

Here is a full review of this excellent, relatively inexpensive "Full HD" (i.e. 1080P resolution) 37" television.

I use this TV with my Panasonic DMP-BD35EB-K Blu-Ray Player, reviewed here

The screen resolution is "Full HD", the highest currently available for TV: 1080 lines, progressively scanned, which is twice the amount of data needed for 720p (720 lines progressive) or 1080i (interlaced) screens, five times as much as 480p (DVD) and ten times as much as 480i (old fashioned wide-screen format) It is therefore far better with bigger screens or close-up. In the shops the Panasonic did appear to be better or at least as good as everything else on display, although all Full HD screens seem to give excellent results with a 1080p source (e.g. blu-ray disc) Contrast is very good and the sharpness and resolution seems far better than my 720p ("HD ready") projector. The colours a far more vibrant than the projector and even my old Sony CRT TV although perhaps a little unnaturally so, but of course these can be turned down. There doesn't appear to be any problem with fast moving images, unlike early large LCD displays and I really can't fault the picture quality with a high-quality 1080p source. Unfortunately I frequently watch TV programmes on Freeview rather than blu-ray or any other HD source and this was a little disappointing in comparison. This is of course to be expected because Freeview only outputs 480 lines and the TV has to upscale the input to create all of that missing data. This is actually quite complicated and it does do a good job in many situations, with a good clean source, but with a poor source (e.g. I tested with a DVD of Not The Nine O'clock News recorded for TV about 25 years ago) the generated pixels are quite apparent i.e. "digital artifacts" sometimes appear and some images can look rather artificial and unnatural. The built-in Freeview tuner is slightly better than my Freeview PVR connected by RGB scart cable and both are better than the built-in analogue tuner. All are tolerable, but not a significant improvement over lower-resolution televisions. Good DVDs give a good clear result and cartoons seem to be particularly good as the upscaling algorithms have nice clean sharp lines and flat colours to work on, although still not as good as blu-ray.

This TV seems very well built and nicely finished with a smooth shiny almost piano-black finish on the front. It sits on a small low stand with 15 degrees of swivel for fine adjustment; a very simple uncluttered design.

I didn't bother listening to this TV before buying it, nor compare it with the competition because I have a good home cinema surround-sound system and five feet tall electrostatic speakers, but for normal TV I won't usually turn the full system on because the built in stereo speakers are really rather good. They lack bass, but are clear and detailed with more than enough power. For a good home cinema experience you will need more speakers for a proper surround-sound affect because the "Simulated Surround Sound" option from the two built-in speakers is not particularly impressive.

The set up is really easy: Simply plug it into the mains, and a coaxial aerial cable into the back and turn it on and the auto-setup tunes the digital and analogue tuners into all available channels. Then you are ready to watch TV. The remote control is large, but quite simple with all of the usual controls and a navigator button to move around the menus and TV guide both of which can be opened with appropriately named buttons. The guide lists all programmes currently on and in the near futures and is easy to read and navigate. If you can find anything worth watching in the huge number of channels click OK.

Screen size: 37" 16:9 ratio widescreen
HDTV: 1080p (1920 x 1080 progressively scanned) frequency 50 Hz
Nicam Stereo speaks (20 Watts) and analogue stereo outputs sockets and digital audio out
Tuner: Analogue and digital (i.e. Freeview) built-in
HDMI inputs: 3
RGB input
Scart sockets: 2
Svideo and composite inputs x 1
PC input x 1
1-year guarantee

This is an excellent, well-made Full HD TV. The only picture quality limitations are those inherent in the input formats I am using. To get full benefit from the TV you will need to use a good quality, preferably Full HD source. I paid £599 from Empire Direct (who have subsequently gone out of business) although it was also available from Currys Digital for £729 and is available from various other shops for about £600.