Techniques of choosing to buy television sets .... NET

Although television is a very close item in our lives, not everyone knows how to choose the best fit for their needs, with room conditions as well as family budget. This article will help you avoid common mistakes when buying this product.

Types of television

Television is divided into 3 main types, which are live TV, front projection television and rear projection television.

Live TV is the most familiar type for us. This type can use traditional lamp technology (CRT), Plasma or LCD screens. When watching this type of television, you will see images directly on the glowing screen appear. The front and rear projection TV that we often see in bars, public places . Its size makes it possible for many people to watch at the same time.

Projectors can be a kind of front-projection television. Antique projectors use 3 small CRT shaped lamps: red, green, blue. These three colors blend together to create all colors in life. Today, most projectors no longer use CRT technology but use LCD or DLP technology, allowing the device to be very light weight and still beautiful.

Rear-projection TVs are often used in the home, also known as big screen TVs. They also have 3-color light sources. These light sources pass through a complex mirror system and are reflected on the back of a plastic screen to create the final image. Now let's talk a bit about the pros and cons of these three types of TVs for you to choose from. The image of live TV (CRT, Plasma, LCD) is the sharpest of the three types because it uses only one glowing light for you to see directly.

In the other two types of television, the visual image should be on the walls or on the plastic screen, then, in fact, you are watching the mirror image, not the image directly on the figure. On the other hand, for television televisions, the perfect combination of the three basic color light sources is very difficult. Therefore, on the screen there will be some corner positions where these 3 colors are not overlapped, it is easy to see the color phenomenon. One thing that is very noticeable for live TV is that you can watch the program even in strong external lighting conditions, and with the TV, you need to watch in the dark room, the new image is sharp.

Compare different types of television

If the live TV can be made in large and cheap sizes, then it is not necessary to discuss, this is the kind of TV we should buy. But the reality is not so, while the size of the television set is constantly expanding, so buyers always have to choose between two criteria: image quality or size. Live TV will be affordable at small and medium sizes, if chosen according to this option, then you will be leaning toward image quality and taking the number of inches down. The rear projection TVs also have the same price, which may be only slightly lower than the live TV, so choosing between this type is not too difficult.

Compared to a projector (a type of front-projection television), it is quite complicated, because it does not include TV tuners, or audio systems, so even if you just want to listen to the version At the end of the day, you also have to turn on the huge hi-fi sound system, as well as turn on the tuner. However, if you want a large screen, this front projection system is ideal because the projector can be mounted on the ceiling, without losing floor area, the camera can be rolled back when not in use. use. In general, with the majority of consumers, live TV and rear projection television is the most economical option.

If you have a need to watch TV greater than 50 ', then think about the rear projection TV. If you want the TV to be smaller, choose the live view because its image quality is much better.

 

When shopping for television, take the time to research the image quality. Different products will have a different display quality.

 

 

TVs often reproduce black and cannot be darker than the screen's black gamut in off mode.

In order to assess this aspect, it is often based on the following factors:

- Blackness of the screen: For many TVs, the blacker the screen when the power is turned off, the higher the contrast. The TV cannot reproduce the black color with darker tones than the screen's black gamut in off mode. Therefore, ordinary screens when powered off but look slightly green, often project images with poor contrast. In contrast, a screen-television must be white, not black.

- Flatness of the screen: This is very important for CRT type TVs. The more flat the screen is, the less light is cast out by the outside light, at the same time, making the image on the screen avoid distortion.

- Another factor to consider when studying image quality is the comb filter function (aliasing is the phenomenon of the sharp and clear image that is deformed like serrated images, often appear on large screens). With small TVs, this disease is hard to see, but TVs from 27 'and above are easy to recognize. Without this function, normal TVs will not be able to handle the correct color and resolution required for the slideshow image. Comb filter will refine the image signal so that the colors and lines are reproduced in the most honest way.

- Finally, with the emergence of digital TV, progressive scan is a new factor you should keep in mind because it also affects the image quality. This new technology is included and both digital TV and DVD. Simply put, continuous scan images are more like plastic films than dramas.

Screen size and viewing position

The phrase 'is bigger and bigger' is probably more true than any other audiovisual device. Experience shows that in most situations, especially with home theater systems, you should choose the screen with the maximum size that the viewing room, seating position and budget allow. Finding a suitable distance between sitting position and screen is very important when watching TV. It helps the image in your eyes become more beautiful, smooth and clear. With small and medium-sized TVs, sitting too car will lose the overall image effect of the device, and with large TVs, sitting too close is not interesting because the pixels or horizontal lines on the screen show up very clearly. makes the viewer feel like he has a tendon or a bed. Find yourself the position where your eyes are most comfortable. According to many documents, the most comfortable sitting position is 3-5 times the diagonal of the screen.

Normal or high resolution resolution

Some families in Vietnam now have digital television, while in the US and many other countries, most households are using it. Digital television includes high definition television and HDTV (standard definition television - SDTV).

HDTV has removed all the limitations of image quality because its image quality is like a plastic film, making the image more detailed, multi-dimensional with richer colors than the 60-year-old analog television. And dolby digital of HDTV sound is also very clear and vivid.

As for SDTV, although the resolution is a bit less, it still delivers a superior image quality of existing cable or satellite television. In your area, the TV programs resolution is still quite strange, you also pay attention to the compatibility of the television you plan to buy with this program. It is like a revolution in television technology and will definitely improve the image quality a lot even if you are not connected with high resolution programs. Most high-definition TVs have built-in upconversion circuitry, so it makes even resolution images become smoother.

Screen size ratio 4: 3 or 16: 9

The transition to digital television systems and the development of DVD format has created a trend to lift the 4: 3 TV to 16: 9 (widescreen or widescreen). Most analog TVs have a 4: 3 ratio, while high-definition TVs are 16: 9. So, which one should you choose?

If you rarely watch DVDs and often watch TV, and you don't have access to satellite or cable programming, you can still choose 4: 3. With high definition television, 4: 3, if you want to watch 16: 9 shows, the TV must have a special presentation mode. Of course, there will be two black bands at the top and bottom of the screen that are symmetrical across the 16: 9 frame.

 

 

Television screened after Toshiba 65HM84.

But if you have access to high-definition TV signals, or you really like watching widescreen DVD movies like in theaters, the 16: 9 screen is the most appropriate option. . The TV can also show 4: 3 programs in a window in the middle of the screen at the same rate as the two black bands lying on the side of the screen. You can also choose one of the available image projection modes to make the images of these programs fill the screen.

Sound of television

Assuming you use the TV for both home theater sets, the built-in surround sound system is a very important factor. You should ask the seller about the specifications such as capacity, speaker size . of this audio system. More importantly, take the time to listen to the TV that performs sound suround through a good quality DVD. Turn the volume up to see if the sound is broken. If so, this is a sign that loudspeakers have poor quality TVs, the capacity is not large enough. In particular, listen to the singing or conversation, when the volume is high, but you feel that it is not clear and difficult to understand, the TV suround system is not completely designed. The cause of this phenomenon is due to the speaker quality and the phenomenon of loudspeaker shake.

 

 

There is no need to purchase an external sound system if the TV has a built-in powerful surround speakers.

In general, the built-in audio system in TV is often quite limited in performance and performance, so you should note this if you plan to purchase a removable suround system. There's no need to spend money buying two surround sound systems while you only have one.

High-resolution televisions have digital audio outputs for streaming dolby digital audio signals. By connecting the TV to the AV receiver via a single digital cable, you can enjoy the clear sound of high-definition television programs.

TV sockets

Now manufacturers have paid more attention to customers' needs and designed many TV inputs including low-cost models. And it is normal for a television with money from 25 'or more but still having enough inputs for 3-5 AV devices (or more).

In the short term, what device do you want to connect the TV to? At least antenna or cable, plus DVD input, and VCR video head. In addition, it could be a satellite TV receiver, a video game system . If you use a camcorder, you will definitely need a set of AV inputs in front of the screen.

 

 

Input type

Plug

Often used for

Coaxial (RF)

Antenna jack

Antenna, cable TV, VCR (video top)

Composite Video

RCA menu

VHS VCR, DBS, DVD, VHS camcorder 8mm, video game

S-Video

4-pin DIN type

Super VHS VCR, DVD, MidiDV and hi8 camcorder

Component Video

3 RCA plugs

DVD, HDTV tuner

DVI

Multi legs

Tuner HDTV, computer, DVD

HDMI

Multi legs

Tuner HDTV, DVD, HD DVR

Remote control

See if it can hold; The function keys are easy to read, some types of controls also have illuminated keys that are convenient for use in dark rooms. Try using all the functions on the control arm. In addition to the usual keys like channel switch, volume, there is a key to adjust brightness, color and sharpness. Audio keys (including bass and treble) can also be integrated on hand. Besides the mute key, the channel selection key (allows you to remove unwanted channels; the device will only display the channels you select when you press the channel switch key); input selection key.

In addition, we should also look at the "Picture in Picture" (PIP) function, which allows you to watch two channels at the same time, which is also included in many TVs. It will be interesting to watch a channel and know what other channels are playing. For this, your TV must have 2 tuners inside.