What are the considerations when you buy an HD TV? Well, the first thing to note is that if you’re buying something new, it’s actually hard not to buy an High Definition set of some sort but, of course, there are a lot of different types of HD and lots of different panels out there, so how do you know which one’s for you?

HD Content

Probably the most important thing to know is how much HD content do you want to watch and how much will you be able to. There’s actually not a hell of a lot of full 1080p HD content out there at the moment.

Sky broadcasts the most at the moment with 36 channels in full HD including BBC HD, all the sports channels and some film channels too. HD programs take up a hell of lot of bandwidth to beam out to people’s homes but Sky can do that because it’s a satellite platform and you can send a hell of a lot of information between satellite dishes.

So, if you’ve got Sky already and you want to get HD programming, then you’re in luck. All you’ll need to do is buy your HDTV, plug it in as usual and Bob’s you uncle, HD in your living room.

Your only other options for HD broadcasts right now Virgin who has just the one HD channel in the shape of BBC HD and Freesat, the free, non-subscription based satellite service from the BBC and ITV. There is a set up charge in that you’ll need a satellite nailed to the the roof of your house and you’ll need a decoder box or a Freesat tuner built-into your TV too but, otherwise, it’s free. At the moment they have just two HD channels – BBC HD and ITV HD – but they have the potential and ambition for a hell of a lot more.

Something like Freeview, on the other hand, currently offers no HD programming and, although they say that they’re going to offer up to four, that’s really as much as they’ll ever have. The reason is that, unlike Sky and Freesat, they’re not a satellite system. They use a certain portion of the electromagentic specturm just like radio but they don’t have very much bandwidth to play with, so, as it stands, they’ll never be able to offer much in the way of HD.

So, if you’ve got Sky, you’re in luck. You’ve got HD as soon as you’ve got you TV. If not then I’d recommend looking out for TVs that have Freesat tuners built in.

That’s all the broadcasters but there are two other ways you can get high-definition content on your HDTV. BLu-rays offer you full HD films and the PS3 and Xbox 360 Elite give you games in full HD too. You can still get 720p HD gaming on the other Xbox 360 models but I’ll get to the difference between 1080p and 720p in a bit. In fact, I’ll do it now.

Screen Resolution – 720p or 1080p

You should now have an idea of how much HD content you’ll be able to get once you’ve bought an HDTV, what it might cost extra to get more HD channels and whether it’s worth you right now buying a Full HD 1080p panel. It may not be. If you’re not going to get much HD progamming you can save you money and buy something 720p instead.

Very quicky and simply, the 720 or 1080 refers to the number of rows of pixels a TV panel will have. The more pixels there are the better the details is going to be. Standard definition or SD sets have 576 rows of pixels, so 720p is already much better than that and 1080p is has around five times the detail of SD. Be careful not to confuse 1080i with 1080p. They are very different. For an excellent description of the difference between i and p watch the video below.

Of course, 1080p panels are going to be more expensive but you needn’t shelll out on one just because it offers better resolution. As we’ve already seen, you might not have that much access to 1080p content but also it’s probably not worth splashing out on all that fine detail if you’re going to be buying a very small TV or if you’re going to sit along way way from it. It’s effectively the same thing. Either way, you won’t really be able to appreciate all that wonderful detail because the picture will be too small.

As a rule of thumb, the optimum viewing distance away from a 1080p HDTV is around 1.5 x the screen size. Therefore you should be sitting around 48″ or 4ft away from a full HD 32″ screen. So, consider saving yourself some cash with a 720p screen if you only want a small panel or you’re going to sit a long way from it.

Contrast

A lot of people will tell you that the next most important feature of a TV is contrast. Contrast is the difference in brightness between the darkest colour on your TV and the brightest part at any given time. You’ll see it as a ration of a very large number to one. A TV with a dynamic contrast of 50,000:1 means that the brightest colour is 50,000 times brighter than the darket colour it can produce. The better the contrast the larger that first number will be. A low contrast ration will mean that there’s not a lot of depth in colour palate and it’ll look fairly lifeless and unexciting.

LCD manufactures have pumped a lot of money into contrast in the last few years because that was one of the early complaints of LCD technology. LCDs are backlight by bright bulbs and it was very hard to get good deep blacks because of the light spill from those back bulbs. If you can’t get good blacks then the difference between the brightest colours and the darkest colours is going to be much less, you’re contrast is going to be much worse and you picture won’t look very good.

Maufacturers seem to have got on top of this recently, though, and you’ll see all sorts of enormous and probably unmeasurable contrast ratios like 1,000,000:1. I wouldn’t take these as gospel but what I would do when you go into a showroom is make sure that they haven’t turned the contrast levels all the way up on the remote to impress you with the colours. It will look colourful but also very unnatural. Particulalry with skin tones. People’s faces will look red. So, make sure you take hold of the remote or get the salesman to show you that the contrast is at a normal level.

Another trick they’ll often try is to turn the brightness down to make sure that the colours look strong and not washed out on sets that aren’t good at showing blacks. It’s another artificial way of making the colours look better but if you bought that set and took it home you’d find that the dark scenes in films look terrible. They’ll be very flat, you won’t be able to see shadows and you’ll miss all the subtelties that the filmmaker intended. That’s why they call ramping up the brightness like that “crushing the blacks” because it kills all the nice, rich, dark moody scenes.

A final tactic is to have some sets under heavy ambient lighting with others in much darker areas of the show room. It’ll make the pictures look very different so bear in mind that a good picture in a very dark room will look a lot less punchy when the lights are up. One way you can get around this is by cupping your hands around your eye and putting them up to the TV screen.

You’ll be blocking out the ambient light and it’ll give you an idea of how good the blacks are.I’d also watch out too for demo discs of cartoons. It’s very hard to judge how natural a picture looks when you’re shown animation.

Frame Rate

So, we know about resolution, we know about contrast. The next is probably the real bugbear for me. That’s frame rate. There’s a few differnt terms that mean more or less the same thing but what we’re talking about is the speed at which the picture on your screen refreshes itself.

As we saw at the beginning when we were talking about the difference between 720p, 1080p and 1080i, the screen has to refresh itself in order to get a moving picture. If it didn’t ever refresh itself then we’d all be looking at the same frame for ever. It’d just be a very expensive photo frame. So, your TV works a little like a flicker book.

What you TV is doing is flicking through the pages so quickly that the eye can’t normally see it. The standard rate that most TVs refresh is at 50Hz, so they do it 50 times each second. Now, normally that’s fine but if the action on the screen is very quick then it won’t look very smooth. Imagine if someone took out every other page of your flicker book. It’s not normally a problem but there are two classic examples in TV watching where you’ll notice it – action films and sport.

You might have seen a bad TV in a pub showing football and you can barely see the passes properly. It sort of has a bit of dream-like or slightly nightmarish qulaity about it and you can’t quite work out what’s going on. That’s because it has a terrible frame rate and the trouble with new TV’s is that they’re getting bigger and as the screen gets bigger, it magnifies all the problems that the set may have.

So, what many manufacturers do now is offer sets with much quicker frame rates. You can buy LCDs that run at 100Hz and even 200Hz now to. They’ll give you much smoother pictures with little or no blur and personally I woudn’t buy anything at less than 100Hz – certainly not for your main TV.

HDMI 1.3

There might be a few other things to consider with your TV such as power consumption. Some panel manufacturers will talk about their green credentials and those TVs will probably save you around £50-£100 in energy bills per year. On the whole, plasma screens are more power hungry than LCDs but they’re beginning to address that now. Besides, although it’s not as clear but as it used to be, you are generally getting a better picture on a plasma but you will be paying a lot for it too.

Perhaps the last important point to discuss is HDMI sockets. HDMI cables are a winderful invention because it’s a way of connecting the audio and video streams to your TV and between other bits of home cinema kit in just one cable each time.

You’ll want your TV to have a good two or three HDMI slots and you should make sure that it’s the newer HDMI 1.3. The newer standard offers billions of colours rather than millions, it’s better at synching up the audio and video and it’s a good place to futureproof your TV because it can also cope with even more resolution than 1080p.

Home Cinema

If you’re serious about you TV and film experience, you might want to consider getting your sound properly set up as well and that’s where all the rest of the home cinema kit comes in but be warned it can all get very expensive.

Traditionally because of the shallow speaker cabinets on flat screen TVs, many models haven’t offered very good sound. These days manufacturers have spent more time looking at the problem and it’s worh watching out for those which have been acoustically tuned by sound engineers. For example, there’s legend in the industry called Mark Levsinson who LG has no got working with them.

But if that’s not enough for you, then you’re going to need a AVR (audio/video receiver) which is a home cinema amplifier. It takes the audio and video from one source – for example, a Blu-ray player – and routes the audio and video signals out without degrading them. It works really nicely with DVDs and Blu-ray discs because the sound track acutally encoded on those discs can then be decoded by your AVR and sent to all the right speakers for the perfect sound experience.

That’s where all the bizarre sounding speaker set up configurations come in. A 5.1 set up refers to having two front speakers (left and right) to rear speakers (left and right) and one centre speaker that you should place either behind, below or above the TV screen. The .1 refers to the subwoofer which can place anywhere in the room.

You can just use two stero speakers at the front of the room if you want to save a little cash but, if you really want to go for it, you can add an extra centre speak at the rear of a 5.1 to make it into a 6.1, you can a place central surround speakers in between your fronts and rears on each side of a 5.1 to make it a 7.1 or, for the full whammy, you can chuck in two more for a 9.1. The additions are actually limitless but of, course, you’ll start to see deminishing returns.

You can buy all in one systems or you get the AVR and speaker sets seperately but bear in mind that it’s worth spending more on the fronts than the others and don’t spend more than double the cost of the fronts on your AVR. Keep the front speakers equidistant from where you sit and angle them in slightly with, if you can fit it, the tweeters at ear level.

Good makes to consider are home cinema kit are Denon, Sony, Onkyo, Pioneer and Yamaha among others and make sure that your AVR and BD players support either, or ideally both, DTS and Dolby Surround sound.

So, now that you’ve digested all of that lot, it’s time to measure up your rooms, count your cash and get down to the shops. I’d advise going to see the equipment first hand before you make your mind up and them going back and buying it online. You’ll often get a better price and 14 day money back period not always available in the shops.