A tone, which starts at 200Hz and transitions down to 20Hz, is generated in the left, center and right channels during this test. The purpose of the test is to alert you to any frequencies that might drop out or not be faithfully reproduced as your Left-Center-Right speakers crossover to the subwoofer. Listen for a drop in volume level during the transition. A high quality system will reproduce the tone sweep smoothly and without volume level fluctuations as the frequency decreases. Systems that appear to vary in audible levels may need further diagnosis. Although any problems maybe inherent in the system, it is important to know what your sound system is capable of reproducing. Faults may be due to a variety of reasons, but the best resource would be your local home theater salesperson. They may suggest a variety of options for you to try. Don’t forget to check out the THX recommended list of home products!

Sounds can be mixed between channels so that they appear centered between the channels or dispersed in nature. If an effect is to sound centered between two channels, an identical level of sound will be directed to each of the two channels desired “in-phase” with each other. The same signal but “out-of-phase” with each other will produce a wide and dispersed sound image. Improper speaker wiring can produce an out-of-phase image by reversing the two wires that feed the speaker. Proper speaker phase is not only important for the front left and right channels, but the center and surround channels as well.

During each Phase Test, the two speakers indicated on the still graphic will emit test tones that alternate being in-phase and out-of-phase. By observing the sound image that is produced by each speaker test sequence, you will be able to determine if your speakers are correctly wired. Listen to these tests by positioning yourself centered between the speakers under test. “In-Phase” will produce a sound image centered between the channels under test while “Out-of-Phase” will produce a sound image that is wide and dispersed and difficult to localize. If you hear an out-of-phase sound image when the image is supposed to be in-phase, and vice versa, turn off your audio amplifier. Next, reverse the wires that feed the speaker highlighted with a red box in the still graphic. Once this correction is made, verify that the correct sound images are now being reproduced, and then proceed to the next test.

Note: This test is most effective for 5.1-channel or 7.1-channel systems only. If your audio system has only two channels, you may reference the left and right front test only. If you have a 7.1 system, the phase tests for the surround channels will appear in the surround back channels during the in-phase test and in the surround left and surround right channels during the out-of-phase test.

Improper volume levels for each speaker is a common problem with home theater systems. In multi-channel sound systems, the sound level for each speaker must be properly set to ensure accurate soundtrack reproduction. In the making of a movie, hours are often spent in THX certified mixing rooms mixing the audio tracks to precise levels to add to the realism and enjoyment of the motion picture. If the levels are improperly set in your home system, the audio imaging will be incorrect, affecting the accurate reproduction of everything from dialog to sound effects to the music track.

In order to check for a balanced audio system, sit where you would normally enjoy your home theater system. Then, listen to the series of test tones and be sure that each sounds equal in volume. Please note that these tones are not for adjusting the volume level of each speaker. Instead, this test is solely an aid in identifying improper level settings. You should use your receiver’s internal test tones to properly set each speaker’s volume level. Only these internal tones should be used for critical adjustment of your system’s volume level for each individual channel. If you have a THX certified home system, contact your certified Home THX dealer for alignment information for your particular system.

NOTE: If you are evaluating a two-channel system, you are concerned with only the left and right channels. If you are using a Dolby Pro-Logic system, remember that there is no distinction between the left surround and right surround channels. If you have a 5.1 system, the surround back channels will play in both the surround left and surround right channels simultaneously.

This test looks similar to the 4:3 Aspect Ratio test, but the 16:9 Aspect Ratio test pattern is used to make sure that your DVD player is set to the proper display mode. If you are using a 4:3 monitor, this test is primarily for the DVD player, but you can still use it to check your monitor’s performance (like the 4:3 Aspect Ratio test). If you are using a 16:9 monitor, you can also use this test to check your monitor’s ability to display 16:9 video.

If you are watching a non-anamorphic feature (for example, a Pan-Scan feature or a letterboxed feature that was transferred for a 4:3 television), you can skip this test pattern.

For 4:3 television sets: Your DVD player should be set to display the 4:3 mode. For today’s technology, it will not matter if your DVD player is set for 4:3 letterbox or 4:3 pan-scan. Consult your DVD player owner’s manual for more information. Widescreen anamorphic movies viewed on a standard 4:3 television must “letterbox” the image in order to display the proper aspect ratio. The DVD player most often achieves this by removing the extra lines of resolution so that the proper number of lines remain. By removing these lines, the anamorphic image is “unsqueezed” to display the proper number of vertical lines for the horizontal width of the television and black mattes are added above and below the image. For this test, the test pattern with the circle will be “letterboxed” and you should see a round circle surrounded by two rectangles (see Figures 13-14).

For 16:9 television sets: Some monitors offer sizing controls that first require an adjustment of the 4:3 mode. Be sure to check and verify the 4:3 circle before making any adjustments to the 16:9 mode. Then, for this test set your DVD player to display the 16:9 mode and set your monitor to display widescreen. Consult your DVD player owner’s manual for more information. You should see a round circle if your DVD player is set-up correctly for 16:9 display (see Figures 15-17). In addition to the circle displayed, you will find two boxes that can be used to check the video monitor’s centering, both horizontally and vertically.

Check with your service technician before attempting to make any adjustments on you home theater equipment. Although you may not fix any existing display errors without the help of a service technician, it is important to provide enough information to the service technician so they may arrive prepared.

*The THX Optimizer test signals displayed are for reference use only. Be sure to check your equipment’s operations manual or refer to your service technician before making any internal adjustments on your monitor.

The 4:3 aspect ratio circle and boxes will determine your video monitor’s alignment for a 4:3 aspect ratio display.

For 4:3 television sets: You should be able to see two rectangles and a perfect circle centered horizontally and vertically on your screen. This test can indicate a misaligned deflection coil as well. If your monitor displays the test pattern off to one side, this would indicate an improper centering adjustment. If you can not see the outer rectangle, the monitor is not sized properly to the point where you actually are missing parts of the picture. You will also be able to determine the areas of your monitor where the display is not consistent — the lines of the rectangle should be perfectly straight while the circle should be perfectly round. Wavy lines or squeezing of the circle indicate problems with the display.

Using the 4:3 signal for 16:9 television sets: The 4:3 circle test should normally be used first to align your monitor’s horizontal and vertical sizing before setting the 16:9 aspect ratio sizing. In most consumer monitors, the 16:9 sizing controls are switched in-line with the 4:3 controls, making the adjustment interactive between the two modes; the 4:3 settings affect the display of the 16:9 setting, and vice versa. For this test, set your monitor to 4:3 mode. You should see two rectangles and a perfect circle centered horizontally and vertically on your screen. This test will tell you if your monitor displays the 4:3 mode properly centered. As in the previous test, you will be able to determine the areas of your monitor where the display is not consistent — the rectangle’s lines should be perfectly straight while the circle should be perfectly round. Wavy lines or squeezing of the circle indicate problems with the display.

Check with your service technician before attempting to make any adjustments on you home theater equipment. Although you can’t fix any existing display errors without the help of a service technician, it is important to provide enough information to the service technician so they may arrive prepared.

*The THX Optimizer test signals displayed are for reference use only. Be sure to check your equipment’s operations manual or refer to your service technician before making any internal adjustments on your monitor.

New THX Optimizer feature

A Multi-burst signal has been added to the Monitor Performance test pattern for the purpose of assisting you in adjusting your television/monitor’s Sharpness control. This procedure is designed to let you optimize the way the overall television/monitor’s picture resolution looks.

Note: While this setting is often determined by personal preference, an optimal adjustment will ensure you presentation as intended by the film’s director.

Adjust your Sharpness control until the lines (see Figure 10) in the multi-burst signal become “edgy”, then reduce the setting until the lines are well defined, but not overly enhanced. Over adjusting can cause the picture to appear too “crisp”, while under adjusting can make the picture appear to be “soft” or slightly out of focus.

The Sharpness control setting is subjective to the viewer. Applying too much sharpness will make the picture appear noisy while the proper setting will produce a sharp picture without the noise.

If you do not have THX blue filter glasses, the Color Bars portion of the Monitor Performance pattern can also be used to adjust your television/monitor’s color and tint. Adjust your Color control so that the red box is red, but not bleeding. Next, adjust your Tint/Hue control until the Cyan (see Figure 10) and Magenta (see Figure 10) boxes are truly cyan and magenta in color.

Your television or video monitor’s overall performance can be assessed using this useful signal. The white crosshatch pattern lets you determine the existence of convergence errors.

Convergence errors are seen as color edges on the white bars (see Figure 11). Perfect convergence is desirable but seldom achievable in consumer monitors. For a closer examination of convergence errors, use the white dots. The objective is to minimize the number of convergence errors. A 10-step grayscale is included that can expose any misalignment in the monitor’s color balance adjustments (see Figure 12). Misalignments can show up as a slight color tinting of the black and white content in the 10-step grayscale.

Color balance errors can occur in the process of displaying a picture on the screen, when the video signal is converted into separate red, green and blue “components” to drive each of the picture tube’s three electron guns. Incorrect settings between the separate red, green or blue circuits can cause one channel to respond differently than the others.

Convergence errors and other color balance problems affect not only black and white content, but color images as well. As this involves a fairly intensive understanding of your monitor’s alignment section, you should call an experienced service technician to perform any of these adjustments on your monitor. The picture tube relies on magnetic energy to move the dots of color, and any movement or re-direction of your monitor can cause changes in alignment due to stray magnetic fields or charges that can remain on the picture tube’s inner components. Just transporting the monitor from the service technician’s place of business to your home can disrupt these sensitive settings, so adjustments should be performed in your home with the monitor placed in its viewing location. The monitor should also be facing the general direction that it will face when used as even the magnetic flux of the earth can effect this setting.

Note: This test requires the use of the THX blue filter glasses. If you do not have the glasses see the order information at the bottom of this page.

With the glasses on, or using the proper blue filter gel, adjust your Color control until each letter in the word “COLOR” is the same shade of blue. Tint/Hue is set by doing the same thing with your Tint/Hue control for each letter in the word “TINT”. Figure 6 shows an example of correct settings for Color and Tint when looking through the THX blue filter glasses while Figure 7 shows an example of incorrect settings for Color and Tint.

Due to emerging display technologies, such as Quattron or RGB+Y, methods of adjusting Color and Tint with blue filters or blue filter glasses will not provide the most balanced image. On products featuring these technologies, jump forward to the Picture Performance Test to adjust Color and Tint.

For the brightness test, THX Optimizer provides a signal that displays two bars containing ten shades of black at the top and bottom of the screen, the THX logo, and a drop shadow behind the THX logo. The THX logo is just slightly lighter than (or above) “black” and the drop shadow is just slightly darker than (or below) “black”. The background area is considered the true “black” for your television. The two shades or levels of black are known as pluge.

The goal is to use your brightness adjustment to make the THX logo (lighter than/above “black”) barely visible, while making the drop shadow (darker than/below “black”) blend into the surrounding “black” areas (see Figures 2-4).

Note: Some DVD players may not be able to play back video levels below “black”, so you may not be able to see the drop shadow or the three darkest shades of the ten black boxes. Figure 5 shows an example of what the test pattern looks like if you have one of these players and the brightness control is turned up. To determine whether your DVD player cannot display levels below “black”, turn up your brightness control and count how many boxes you can see at the top and bottom of the screen.
If you can only see seven shades of black boxes, your player cannot display levels below “black”. However, you can still correctly set-up your Brightness level by following the next instructions. Turn down the brightness control until you can no longer see the seventh darkest shade of black at the top and bottom of the screen. Then, turn up the brightness control until you can barely see the seventh darkest box.

The Brightness adjustment can be very important for some projection televisions since the black content of the video can contain video noise or hum, which can be detrimental to the picture. It’s important, therefore, in the case of a projection television to position yourself at the proper angle that allows full brightness to be observed from the picture screen.

Video is measured on expensive test equipment during the post production process. The scale on a waveform monitor is graduated in IRE units (Institute of Radio Engineers, the group that set this measurement standard). For DVD component video, the useful picture content of the video signal is measured as a percentage, where 0% represents black and 100% is white. With VHS, Broadcast and the composite video output of your DVD player, the black level for NTSC is elevated to 7.5% IRE. Normally, the picture intensity is clipped, or not allowed to exceed 100% IRE and little if any information transitions above this level.

The Contrast/Picture adjustment procedure provides a box with four distinct shades of white in eight boxes surrounded by black.
If the Contrast/Picture control is set too high, you can lose the distinction between the various white boxes and can result in picture bleeding, which is the oversaturation of the picture tube. This can be seen as a solarization or blooming of the picture highlights (see Figure 1). This can also be noticed on the right side of the white block as it transitions to black due to the way the picture tube is scanned. The brightest white boxes will represent the highest video level in the feature. The goal here is to adjust your Contrast/Picture control on your television/monitor to a point where the large white area is bright but all four shades of white are still visible. At the same time, insure that the transitions from black to white and white to black have no smearing.

As your picture tube ages, this will be one of the more difficult adjustments to make. The light level produced by the picture tube decreases with age, making it necessary to drive the picture tube harder. The harder the picture tube is driven, the less likely the beam scanning the front of the screen remains sharply focused. If you notice any of the mentioned defects, it doesn’t mean you need a new monitor or television. It may only require a visit from your local television service agency to make some adjustments.