Home theater viewing angles, distances and sightlines

Horizontal Viewing Angles

The horizontal viewing angle is the angle subtended by a straight line from each side of the screen to the seating position. The main two standards in the commercial world are the SMPTE and THX specifications as summarized in the diagram below:

New cinemas built to THX specifications have a minimum viewing angle of 36 degrees from the last row of seats. The viewing angle ‘sweet spot’ seems to be around 45-50 degrees where SMPTE, THX and 20th Century Fox recommendations converge. This matches quite closely with CEDIA’s 43 degree viewing angle recommendation for 2.4:1 ‘Cinemascope’ content as per CEB-23. For reference 43 degrees is 3x picture height using a 2.35:1 screen.

Depending on where you like to sit in a commercial theater you might have a viewing angle of anywhere from 36 to 60 degrees. Personal preference is therefore an important factor and should be a prime consideration when laying out your home theater.

 

Image Resolution and Horizontal Viewing Angles

Visual acuity data give us useful information about when a person should be able to appreciate the full benefit of different resolutions.

  • 480p – 4.1x width
  • 720p – 2.7x width
  • 1080p – 1.7x width (equivalent to 33 degrees viewing angle with a 2.35:1 screen)
  • 4k – 0.8x width (over 60 degrees viewing angle with a 2.35:1 screen!)

Higher resolutions should allow us to sit closer to the screen for a more immersive experience. Likewise with lower resolutions we may want a smaller viewing angle so that deficiencies in the source’s resolution are not overly exposed.

 

Vertical Viewing Angles

The CEDIA recommendation, which is based on SMPTE guidance, is or no viewer to have an angle of greater than 15 degrees to the top or bottom of the screen. Typically this puts viewers eye’s at 1/3rd to 1/6th of screen height.

 

 

Dealing With Multiple Rows of Seats

In larger home theaters multiple rows of seats are common. This introduces some compromises and challenges:

  • Horizontal viewing angles. Due to the smaller screen sizes and viewing distances in a home theater the viewing angle changes much faster than it would do in a cinema. A front row in a theater with three rows of seats might have a viewing angle of as much as 60 degrees with the back row only 26 degrees.
  • Sightlines. With more than one row sightlines from second and subsequent rows to the screen can be blocked by viewer’s heads. Typically this is dealt with using seating risers or horizontally staggered seating layouts. When using risers one must be careful not to exceed vertical viewing angle recommendations.

 

Need help laying out your home theater screen and seating locations for proper viewing angles? Contact us now!

 

2 thoughts on “Home theater viewing angles, distances and sightlines”

  1. I’m thinking of getting either a 87.2″ or 104.6″ wide screen to watch 1.78 and 2.35 aspect ratio movies. This way, if I buy a 16.9 screen and mask it horizontally from the top, I can also watch 2.35 movies with no side or bottom masking.

    The 2.35 movie at 87.2″ would have a 95″ diagonal and at 1.78, it would fit the screen without masking (since that is the standard I would buy).

    Likewise, and 104.6″ wide screen would have a 114″ diagonal and at 2.35, and for the 1.78 aspect ratio, the projection would fit the screen without masking.

    My question is whether the larger format would be too big for my room considering a viewer woud sit about 9 feet in front of the screen in the first row and 14 feet in the last row (2nd row). What do you think – and if it was too big, then is the smaller screen a good option?

    In either case, my masking would simply be a roller blind to reduce the verical size of the screen dimension to watch a 2.35 movie. (Nb, I would mainly watch 2.35 movies, but I thought the 16:9 screen would allow me to watch both formats with not much more work, whereas a 2.35 format screen would of course limit the 1.78 experience.

    Please don’t go to a lot of work, only answer if you can give me your opinion rather simply.

    From another web-site , I calcuated the field angles for the centre of the first row to be 51.9 degrees (2.35, 114″ diag) and 34.7 degrees for the 2nd row and 44.1 degrees in the first row and 29.2 degrees in the second row (2.35, 95″ diag.)

    For the 1.78 aspect ratio, the field angles are:
    (120″ diag: 51.7 and 34.6 degrees)
    and
    (100″ diag: 49.4 and 32.9 degrees)

    1. Hi Haig,

      51 degrees is pushing it, but is still within the realms of possibility. When you go to a commercial cinema, how close do you sit to the screen? 52 degrees is within the front third for sure. The screen in our demo room is 50 degrees 16:9 (1.78:1) aspect ratio and I think it’s workable but some people do find it a bit large!

      For reference the CEDIA recommendation is 33 degrees for a 16:9 screen, which personally I think is a bit small.

      If you go for a large screen you should also make sure the second row can see the screen. Also make sure the top of the screen is not too high for the front row (15 degrees maximum ideally, but you could stretch this to 20 degrees).

      Nyal

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