Q: I bought your book and read the section on how far to sit from an HDTV. According to your example, I should sit closer to a 53-inch HDTV than the distance recommended by another site suggests. I realize that you take the resolution of the HDTV into account and the others don't. Does that explain the difference between your recommendations and theirs?
Mark R.

A: First, let me say thanks for buying my book. And while you included a link to the site you referred to for the conflicting viewing distance recommendation, I have omitted it here because there's no need to pick on any one site. There are many sites that make similar recommendations, and I suspect that many of them are based simply on on information available elsewhere, such as CEDIA's tables.

Many of these sites — if not all — do not explain how they calculate their recommendations. As a result, it is difficult to evaluate them or explain the difference from my results. But clearly, resolution is a major difference. Think about it; a full sheet of a newspaper and a travel poster are about the same size, but the recommended viewing distances for each are very different. If a display is made up of dots, then there is a distance at which the human vision system can't distinguish between the dots. At that point, you won't be able to tell the difference between a higher-resolution (and more expensive) HDTV than one the same size with lower resolution. I think it's intellectually lazy to ignore this factor.

Also most sites — if not all — give you the information backwards. They'll tell you how far to sit from a 42-inch HDTV. But most people aren't starting with the display; they're starting with a room that already has a viewing distance. So in my book, I have you measure the distance, multiply it by a single number, and you get the optimal size display for the room. Simple and easy.

Confused about how big an HDTV you need for your room? Check out Professor Poor's Guide to Buying HDTV.