Video Tests
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Calibrating your Home Theater Video

We are now at the end of the installation of your new system. All that is left now is to calibrate the video of your home theater. As we discussed in the audio calibration section the best way to do this is with a calibration DVD. Why pay a professional a lot of money to do something that not only you can do yourself but it is actually a fun project. You can also re-calibrate any time you move, the temperature changes radically or a new component is added. I like to re-calibrate at the start of winter and summer when the lighting and ambient temperature change. These environmental factors affect the video significantly to make such a re-calibration worth while. The tests take less than an hour of your time and translate to many hours of enjoyable viewing.

Unfortunately, of the three most popular calibration DVDs made, Ultimate DVD Platinum, Video Essentials and Avia, only Avia is still being produced. You can still find used copies of the other two around and the search will be well worth the effort. The cost of one of these discs new is about $40 and considering the use you will get out of it a must have.

Each of these discs will run you through a series of test patterns that permit you to adjust the video attributes of your TV. A few of the tests are best run before you buy the set since a defect is not easily or inexpensively corrected. It is a good idea to take a calibration disc with you when you buy any home theater component. Most reputable dealerships will permit you to run a few simple tests before you make your decision. If they donít, well itís your money, you have the upper hand, go somewhere else and they the manager know why.

A few tips before you start of the tests. Make sure your room is lit in manner typical of your viewing habits. If you primarily watch in the evening run the tests then, not in the brightness of the day. Remember that a lot of the tests are subjective. Use them only as a guide not an absolute. You are the most important piece of test equipment around. No meter will be watching the TV, you and your family will. Involve your family in the testing. Kids love to help in this. Let them tell you when the test criteria are met. A universal remote helps a lot here. It will keep you from constantly shuttling between the remotes for the DVD player and the TV. If you have learning remote make sure the functions for calibration are included. Once the TV is properly calibrated the picture most likely will seem very dark to you. Almost all TVs come out of the factory with the brightness and contrast pushed way too high. This is to show them off better under the excessively bright lights in the store. Donít worry, in a week or so you will wonder how you ever watched a movie with the settings so bright.

Brightness, this sets the reference point for the black level. It set too high true black tones will appear smoky. If too low there will be a loss of detail. The pattern is called a pluge. There are two sets of rectangles of various shades of black to grey and then to white. When you set the brightness you increase until the set sets are about equally visible.

Contrast, this sets the whiteness level of the picture. If set too low the picture will be dark and muddy, too low and the white areas will bloom and overwhelm the details. The test uses a modified cross hatch pattern. There are a lot of little lines. You adjust the setting until the lines just begin to blur.

Monitor purity test assures that your monitor displays all colors equally. For regular televisions there is a test pattern of 90% white and primary red. If other colors are seen you have to demagnetize your set. For a flat panel or plasma display the test pattern is made up of red, blue and green. If other colors show during the pure color displays you have pixels that are not functioning. Unfortunately, the only way to fix this problem is to replace your set.

Geometry tests help you adjust the proper aspect ratio of your set. There are three tests in this suite, standard 4:3, letterbox and anamorphic 16:9 wide screen. The test screen is a large circle in the middle of the screen and four smaller circles in each corner. If any circles are elongated you made need a professional adjustment.

Convergence test, tests for proper alignment of the red, green and blue color guns. It is not useful on plasma screen displays. It uses a cross hatch of lines and dots. You adjust your set until the three sets of colored lines merge into a white line.

Chroma test looks at the correct level of color ad provides a life like representation of the colors. It is only for S-Video and composite connections. It uses a SMPTE color bar set (the old test pattern on many broadcast stations) and a blue filter for you to look through. When you use the blue filter on the colored bars you will see only blue and black. You adjust the chroma settings until a light blue bar just begins to appear at the bottom of several of the black bars.

Hue test adjusts the settings of the correct color phase for your display. It is also for those systems connected by S-Video and composite video. It is also called the phase or tint test. Like the chroma test it uses SMPTE color bars and the blue filter. You make the adjustment until a dark blue patch appears at the bottom of the far left test bars. When the setting is correct the top and bottom of the bar are the same color.

Clamp test provides a test for the ability to maintain correct black color level during high contrast transitions. This should be done when you are buying a set since there is little that can be done for a set that fails. It uses black and white transitions screens. There is a flickering white and black background with a black square in the middle. If the black level of the square changes during the change in background from black to white the set passes the test.

Sharpness tests whether the image will appear soft of very sharp. This is a very subject test. Too little sharpness will provide a soft, diffuse picture while too much will create a lot of noise; It uses a multi-burst test pattern of a series of vertical bars on increasing width. As you increase the sharpness the contrast will change in the right most, smaller, bars. You adjust the control until you see about the same level of contrast across the whole test pattern.

Well, now comes the moment we waited so long for, put your favorite DVD in the player, crank up the sound, dim the lights and enjoy.

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