The most favorable TV screen size is totally associated with the available viewing distance. Conversely, there are added factors also that need to be taken into account.
Viewing Distance: Is it simply an issue of personal inclination?
Sit exceedingly close to your big screen television and you would be able to see the image build-up structure – scanning lines or pixels figuring the picture, thus diverting your concentration and ruining your home theater experience. Nevertheless, take a seat excessively far away, and the impact will be lost.
The reality is that there are no technical rules here. This does not mean that there aren’t any guidelines that you have to adhere to when preparing for a big screen purchase or a prospective home theater place.
SMPTE Recommendations and the THX Certification standards:
The Society of Motion Pictures and Television Engineers (SMPTE) recommends that the screen size for home theater utility should take up a 30 degrees area of view – in the horizontal plan – for the viewers. On the other hand, the ultimate television viewing distance needs to be such that the screen width uses an angle of 30 degrees from the watching place.
This SMPTE principle is also similar to the THX certification guidelines in that these suggest that the rear line up of seats should have a minimum of a 26 degrees watching angle and while recommending a most advantageous watching angle of 36 degrees.
So How Does All This Translate In Practical Terms?
A general rule for the television viewing distance according to the SMPTE and visual acuity principles, is that the nearest TV viewing distance between you and your big screen TV should be restricted to nearly double the screen width (more accurate 1.87 x screen width for a subtended angle of 30 degrees), while the furthermost distance being just five times the width of your screen.
But, it’s additionally critical to comprehend that these maximum and smallest possible viewing distances ought to be observed in the light of the video signal definition.
A completely resolved HD TV (1080i, 1920×1080) supports a closer watching distance than ordinary analog TV. While twice the screen width would be the perfect television viewing distance for a HDTV display, it would be a bit too near for customary TV; in the later case, a thrice the screen width would be a greater option.
When it speaking about the use of regular-size standard definition analog TVs in the home theater, i.e. approximately 36 / 40 diagonal, the finest watching distance range is between 8 feet and 12 feet. television sets smaller than 36-inches are not big enough to qualify for Home Theater use since their smaller screen size will not provide the preferred impact on the watcher.
Vertical Angle of View & Screen Height:
For optimal watching, the sight of the viewer should be at equal height with the hub of the screen.
Maximum vertical angle of view: In those home theater set-ups where this is not possible, the SMPTE guidelines recommend that the maximum vertical angle estimated at the seated eye height from the front row middle position to the highest segment of the projected image should not go beyond 35 degrees.
This doesn’t stand for the most favorable viewing angle but rather the constraint from which the watcher would be put through an intensified neck strain.
Minimum angle of vision: While there do not appear to be any identifiable SMPTE or THX principles in this regard, research have shown that if the screen dimension occupies below 15 degrees of the watcher’s vertical field of view, then that image looks as if it were minute.
Practical Matters:
In a classic home theater set-up, you don’t have to actually be concerned concerning neither the maximum vertical angle of view, nor about the tiniest vertical angle of vision for an effective movie theater experience.
If you were to keep to the commended television viewing distance of double the screen width (as additionally detailed previously according to the SMPTE principle of 30 degrees horizontal field of vision), you would mindlessly be sticking to the least possible angle of vision. The reason behind that is there is a permanent relation between screen height and width in accordance to your home theater screen aspect ratio of either 16:9 or 4:3.
Taking into consideration that the largest part of home theater rooms are around 10 feet (3m) high, the ensuing vertical watching angle is typical well within the maximum of 35 degrees detailed in the SMPTE principles, all you should do is simply remain within the twofold the screen width principle for your watching distance.
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