the 4 times the height rule...what source is that for? obviously cable at for times the height will look a whole lot worse than a dvd and much worse than HDTV. i'm looking into buying a 57" set. the recommended seating distance at 4 times the height would be just over 9 feet, but i'm wondering whether i will be able to watch my digital cable from that distance.
What you need to understand is that the resolution of the Pioneer and most other HD rear projection TV's is similar to a line doubled signal. Your regular 480i signals are being upconverted to 480p, native 480p signals are shown as is on most sets, and 1080i is native. Effectively the maximum stable resolution of any of these signal, whether native or processed is 480 lines per field, 2 fields per frame, 30 frames per second. Remember, 1080i only scans half the lines per field.
This is not to say the the image quality from all sources are the same, but that if the average stable resolution of the display is 480p, that would be the number that I would use for the calculation.
Just so that you understand, I am not offering just an opinion here. The range I stated originally is commonly accepted as the recommended practice by the consumer and professional industry. If you use the SMPTE recommended practice for regular NTSC 480i signals, seating distance is 4-8 times the pic height. In my original training as an ISF tech 5 years ago, Joe Kane stated that 5 times the pic height was his recommendation for NTSC signals. His recommendation was based on real world experience and application.
As the displayed resolution increases, one has the choice of either a larger display for their fixed seating position, or the ability to move seating closer to the monitor. A persons vision plays a crucial role but with multiple viewers, some compromise must be made. Even though I have perfect vision, I remember when I could sit in the front row of a movie theater. Today, like most adults, I sit towards the rear of the theater. The distance my eyes need to focus on moving objects has changed.
This is why there is a recommended range and not just a specific number. Many front projection companies offer basic programs that calculate seating distance based on your input. You may want to check them out.
If a source is bad, changing the distance by which it is viewed will not improve it. Garbage In and Garbage Out.
I hope this helps clarify the reasons for my recommendation.
The correct answer is not to be found on any calculator or web site. The correct answer for you is personal and you will decide when you have the set in front of you. I prefer distances much greater than the "correct" distance. Some prefer to be jammed in front of the set.
None of us are right, but for our own selves, we are infinitely more correct than a web-based calculator or a 4x the screen height rule.
In some respects I agree with your comments. But, there is good advice and bad advice out here on the forums. Attempting to help a person understand his/her options and how these decisions affect their home theater experience is the best we can do. Ultimately, it is up to each individual regarding how they implement the professional standards and recommendations.
I went with the Hitachi 43uwx10b-I was also looking at the JVC 48inch widescreen, but decided that sitting at 7ft would be too close. Right now, I am very happy with my purchase HBOHD & ShowtimeHD looks great-so do DVDs. Analog cable isnt that bad either. Thanks for your help
What about the 'below' viewing angle?? The Panasonic 47" set that I'm thinking about getting will be aprox. 8.5' away, and will be on a raised platform (7") - I don't think that when i 'sit' on my couch this will be a problem, but if I wanna lie down will the picture be vastly afftected?? In the showroom when I kneel down and look at the screen on all RPTV the brightness really drops off...
SMPTE recommends a maximum vertical "viewing angle" of 35 degrees to the center of the screen. For a 8.5' viewing distance that gives you nearly 5' above "eye level" to work with. Angles greater than that are likely to induce neck strain.
Originally posted by mysphyt Here is a link to another viewing distance calculator. Based on SMPTE and THX recommendations for Cinemas as well as some recommended video viewing distances from Electrohome.
The SMPTE standard Mysphyt spoke of may not apply to rear projection, especially consumer pre-built designs. Wasn't this standard written for ceiling mounted front projection systems(i.e film projectors in commercial theaters)? I would appreciate it if you could tell us the SMPTE standard # or Recommended Practice # for my own personal reference.
One of the biggest problems with placing a rear projection too much above eye level is that these units are designed for limited vertical off-axis dispersion. This allows the manufacturers to focus their attention on a wider horizontal viewing plane which is more critical for the average living room.
Ultimately, you will lose picture dynamics or light output and you can't afford to give that up on a CRT designed product. One way to test this is to sit at eye level at your seating distance(TV at floor level) and then stand-up. Usually you will notice that the image is not as bright when viewing standing up. This would be the same in reverse. If the TV is above your eye level, you will experience the same problem. Of course, if your seating is higher than a normal sofa or chair, a seven inch platform riser may benefit you by raising the TV closer to eye level.
The amount of light output loss on the vertical plane will vary from model to model and brand to brand. Some manufacturers may list vertical dispersion numbers but it is best to just do the simple test.
Give it a try and keep us up-to-date on the results.
I got the Hitachi home Sat. & I love it, but it does have the dreaded "bulls-eye" problem that I will have to address. The set was made in March of 2002-I thought Hitachi would have solved this problem by now.
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