Ed's AV Handbook.com
Home Theater & High Fidelity Stereo Audio



Chapter Six
The Room, Speaker, & TV

Page 6

Batting practice for the audio/video pro and a primer for the novice
 


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The TV

 

            Picture this - your speaker system is perfectly placed.  You have successfully managed acoustical problems in your quiet room.  You are seated in a perfect position to listen and
view your new re-mastered UltraHD BluRay disc of
Animal House or The Seventh Seal.
Yet there is something missing from this audio/video picture.  That’s correct.  It’s missing the picture; That's next.

Defining the TV
          The term TV for the purposes of this discussion includes video displays that range from a dedicated home theater room with a projector focused on a 10-foot screen to a 40 inch TV sitting in a family room.

Room Lighting
          UltraHD and HDTV offer an exciting potential for higher picture resolution.  However, increasing resolution can result in less light output from the TV.   Conversely, increased light output can distort resolution.  Therefore, a darker room is essential if the high-resolution potential of the video is to be achieved.   You might ask “how dark?”  There are two scenarios. Each has a different answer.
          The first scenario specifies a completely dark room.  This is a front projection system displayed on a large screen.  Light from other sources will compete with the projected video. This is the reasoning for omitting windows in a movie theater, and this was the incentive for closing a 1960s drive-in movie theater in the daytime.  Do you see the picture?  Block all light.
          The second scenario uses a direct view LCD, Plasma, or OLED TV.  In a completely dark room this type of TV can cause painful eye strain in a relatively short period of time.   This is due to the iris of the eye opening and closing as scenes change from dark to light.  For an effective demonstration, turn your back to a TV in a darkened room.  Observe how the intensity and frequency of the light changes in the room.
          A neutral color fluorescent lamp with a brightness control can solve the problem.  
Place the lamp behind the TV aimed towards the wall.   Adjust the brightness until a small amount of ambient light reflects off the wall.  The reflected light reduces the range of motion in the iris and allows the eye to relax.  This will permit many hours of comfortable viewing.

Ambient Room Lighting & Color
          HDR UltraHDTV offers an amazing palate of color.  However, any reflected color within your field of vision will affect your perception of the TV’s color. Therefore, choose suitable colors for all room boundaries.
          For example, if a direct view LCD or OLED TV is used -- choose wall colors of low color temperature such as neutral gray for all room boundaries (reference gray card).   Art, fabric, or any objects within the field of vision should also be limited to neutral colors.  Typical off-whites and vivid colors will distort the viewer’s perception.
          If a front projection TV system is used, paint the room flat black.  This will absorb residual ambient light from the projector and screen.  If a completely black room is aesthetically unacceptable, then at least blacken the ceiling area from the projector to the screen. Choose dark colors for the remainder of the room.  In addition, a black trim around the screen will appear to provide better contrast.

How far should you sit from the screen?
          As a general rule the Society of Motion Picture and Television Engineers (SMPTE), recommends that you sit a distance of at least 1.5 times the width of the screen.  The issue is any motion beyond 40 degrees of lateral viewing can cause excessive head movement and discomfort.  Therefore, select seating positions that keep the image within forty degrees.  The SMPTE recommendation acomplishes this goal.  As a final point, consider the acoustical issues previously discussed and maintain a good listening position.


Loose ends
          If high performance video is your goal, then a qualified ISF (Imaging Science Foundation) trained TV calibrator should be hired to calibrate color and gray scale. An uncalibrated TV will perform as well as an un-tuned piano, or an un-tuned high performance car.  
             Install dedicated electrical circuits for the system electronics.  Provide 15 to 20 ampere circuits with hospital grade electrical outlets.  Consider the addition of AC line conditioning and a current stabilizer.  The sum of the above will isolate your electronics from electrical circuit noise and stabilize AC power.
          Heat is an enemy of the system’s electronics.  Therefore, provide ample cabinet ventilation.  You may need the assistance of a ventilation fan.  Choose a cabinet with easy access.  This will make it easier to install and maintain the system components.
          Here are some suggested audio/video tools for setting up your system:
               – Sound pressure level meter
               – Tape measure
               – Pink & White noise generator
               – Several CDs and BluRay discs with musical & movie examples
               – Joe Kane’s Video Essentials
               – The Optical Alignment Kit by Acoustic Sciences Corporation
               – Q-Tips
 .... yes, for your ears.

Quite expertly handled
          Outstanding high fidelity audio and UHD video has been achieved.  The room design is quiet.  Your listening position, the speakers, and the calibrated TV are in place.  The room’s acoustics, color, and lighting are expertly handled.  And your spouse is pleased.  You are now ready to enjoy your high performance high end audio/video system.

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Ed's AV Handbook.com
Batting Practice for the AV Pro and a Primer for the Novice.
Copyright 2007 Txu1-598-288   Revised 2018