The method
Cinema designers check sightlines row by row with a simple construction from the UNIC handbook: draw the line from each row’s eyes to the bottom of the picture, and measure how far it passes above the eyes of the row in front. That distance is the C-value. UNIC rates 200 mm (7.9 in) or more as good, 150–200 mm acceptable, 120–150 mm poor, and less than 120 mm unacceptable.
The required back-row eye height follows from similar triangles: it equals the picture’s bottom height plus the front row’s eye height plus C minus the picture’s bottom height, scaled by the ratio of the two rows’ distances from the screen. The riser is the difference between that and the front row’s eye height, assuming identical seats.
C is measured from the eyes, not the top of the head. The ANSUR II survey puts the median distance from eyes to the top of the head at about 4.3 inches for women and 4.5 for men, so a C of 150 mm leaves roughly 1½ inches above a median head.
Questions people ask
How high should a home theater riser be?
It depends on your screen height and row spacing, not a fixed number. With the picture’s bottom edge 30 inches up, the front row 11 feet from the screen and rows 6.5 feet apart, the back row needs a riser of about 17 inches for an acceptable sightline (C = 150 mm) and about 20 inches for a good one (C = 200 mm). Raising the screen’s bottom edge to 36 inches brings those down to about 13 and 16 inches.
What is a C-value?
The distance by which the back row’s line of sight to the bottom of the picture clears the front row’s eyes. The UNIC cinema handbook rates 200 mm or more as good, 150–200 mm acceptable and 120–150 mm poor. It is measured at eye height, so it includes the 4 to 5 inches from eyes to the top of the head.
How far apart should theater recliner rows be?
Far enough for the front recliner to fully extend plus a walkway. A La-Z-Boy Pinnacle wall recliner is 64.5 inches deep fully extended, so rows of recliners commonly end up 6 to 7 feet apart, back to back.
Sources
- International Union of Cinemas (UNIC) (2021). UNIC Cinema Technology Handbook (v2).Professional guide
- US Army Natick / Penn State Open Lab (2012). ANSUR II Anthropometric Survey of US Army Personnel (public data).Measurement
- La-Z-Boy. Pinnacle Power Wall Recliner (16X512) dimensions.Manufacturer
- Fortress Seating. Theater seating specifications.Manufacturer
Numbers on this page follow these sources. Where a figure is our own calculation or a rule of thumb, the text says so. Found a mistake? Tell us.
