Screen Sizes Explained for HD and Ultra HD Home Cinema Owners

If you are among the elite or merely a connoisseur of cinema, you know already know screen size can make a difference in the quality of your viewing experience. One of the most frequently asked questions that we receive is How do I choose the best screen size for my home theatre?

Screen size is one area which divides couples completely when building their home cinema; the film lover wants the biggest screen possible and the interior designer wants the smallest.

In fact, to gain the best viewing experience, neither are correct. Since the early 1950’s optimum screen size discussions have taken place and several papers have been released. Most recently, Dolby and THX have released recommendations for viewing High Definition (HD) and Ultra High Definition (UHD) material and we have summarised this information here.

Selecting Screen Size in your Home Theatre

Screen size has to be used in context, a 3m wide screen in a small 2.5m x 3.2m room would most certainly be considered too large, but in a 22m x 9m room, it’s probably too small.

To help get some meaningful measurements for best screen size, we use a method often referred to as subtended angle, as shown in figure 1. This removes the room factor and allows us to focus on both the viewing distance and screen size only.

The ideal screen size is therefore best represented as a compromise, albeit the best compromise, and is set by considering several factors:

Source material (High Definition or Standard Definition)

Projector type and brightness

Room layout

Number of seats and location                                 

Seating distance from the screen

Screen type

Screen aspect ratio

The Evolution of Filming Techniques Have Impacted Screen Size

Filming techniques have evolved dramatically and this has quite obviously improved cinema since the 1950’s, so a number of factors have all led to the subtended angle increasing over time. These contributing factors are camera focusing, vibration on the film caused by the shutters in the cameras, scenery and props, and even makeup have influenced these changes. As such, the evolved product has resulted in your ability to create the best possible home cinema experience.

The final decision on screen size is a compromise between Quality and Involvement as shown in Figure 2.

Starting Point

Most industry organisations now consider a 40° subtended angle a good starting point, if your main source is Standard Definition TV then this may be revised closer to 30°, if however all you watch is modern Blu-ray material and you have access to a bright enough projector, 50° may be considered the optimum choice.

Some Examples, assuming 16:9 ratio TV:

Sitting 2m away

40° subtended angle

TV width 1.46m

TV diagonal 65”

Sitting 3m away

30° subtended angle

TV width 1.6m

TV diagonal 70”

Sitting 3m away

40° subtended angle

TV width 2.18m

TV diagonal 100”

Following these guidelines will help you select your screen size and optimize your home cinema experience so you can see, feel, and experience the difference for your friends, your family, and even yourself.

Should you need more specific advise for your unique home cinema, you may reach out to AV Candy, the bespoke multimedia home cinema installation experts.

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