That new 32-inch HDTV you want — how much bigger than your old 32-incher is it?
Actually  . . .  it's smaller! Read on to avoid an expensive mistake.

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As we can see in the example above, the "old" 32-inch TV has 491.52 square inches of screen area, and the 32-inch HDTV has 439.6 square inches — in other words, less. When comparing an "old" TV and HDTV of the same diagonal screen size, the HDTV screen is actually 11 percent smaller. This is true whether comparing 32-, 42, 50- or 60-inch screens: A 60-inch HDTV screen is 11 percent smaller than your old 60-inch non-HD projection screen. To make sure

 

your HDTV has the same screen area as your old TV, it needs to have a diagonal measure ("screen size") that's six percent bigger. (Why not 11 percent? The math involves logarithms and square roots — i.e. Pythagorean geometry, not simple multiplication. Trust us on this.) In other words take the diagonal screen size of the old TV and multiply by 1.06. If you have a 32-inch regular TV, this means the HDTV needs a 34-inch screen if you don't want your new TV picture to be smaller than the old one (32 times 1.06 equals 34). But this is not the whole story, especially when it comes to watching "old" TV shows on your new HDTV. Read on  . . .

The “Seinfeld” Factor

A better yardstick (so to speak) than screen area is screen height. If your new HDTV has a screen that's as tall as your old one, not only will you be sure that you're getting a bigger picture, you'll also be certain that when you watch "old," non-HD programs on your HDTV, the picture you're looking at will not be drastically smaller than the one on your old TV set.

 

BACKGROUND: We're all familiar with "letterboxed" TV -- bands across the top and bottom of the screen when we're watching a widescreen movie on regular TV, for instance. When that situation is reversed — when we're watching a  "narrowscreen" program on HDTV — there are bands to the left and right of the picture. In other words, if we are watching anything from I Love Lucy to Seinfeld, or home videos, the pictures look like this:

 

 

AS YOU CAN SEE from the two 32-inch TVs above (the same TVs shown at the top of the page), watching "regular TV" on an HDTV with the same diagonal screen size as your old TV gives you a picture that's 33 percent smaller — only about two-thirds as big as on your old set! To avoid this pitfall, use this rule of thumb: Make sure your HDTV has a screen that's

 

 

the same height as your old TV screen. To do this without taking a tape measure to Best Buy, you can either do the math yourself, or use our handy chart below. It's based on this simple rule: To find the HDTV screen size (diagonal measure) that gives the same height as your old television, take the screen size of the old TV and multiply by 1.22. So if you want an HDTV with a screen that's the same height as your old 34-inch TV, for example, the chart below shows that you need to buy an HDTV with a 42-inch screen, and that they will both have a height of 20.4 inches. On either TV, a non-HD picture will be the same size. The total HDTV picture area will be one-third greater than the total picture area of the old set.

 

 
Old Screen Size (Diag., Inches) Screen Height HDTV Screen Size (Diag.)
21 12.6 26
27 16.2 33
29 17.4 35
31 18.6 38
32 19.2 39
34 20.4 42
36 21.6 44
40 24.0 49
42 25.2 51
50 30.0 61
55 33.0 67
60 36.0 73
 

Above: If your old TV has a 34-inch screen, for older programs like I Love Lucy, Seinfeld etc. to be the SAME SIZE on your new HDTV, the new TV should have a 42-inch screen.


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