Comparing Contrast

Q. I'm planning on buying a flat-panel TV, but I'm confused about one term: contrast ratio. While comparing various sets, I noticed that their contrast-ratio specifications were vastly different. Some TVs have a contrast ratio of 600:1, while others have a much higher ratio, such as 2,000:1. How important is contrast ratio when selecting a plasma or LCD flat-screen TV?
Fernando Cajero
Via Email

A. Al Griffin says: Contrast ratio, which is the difference between the brightest white and the darkest black that a TV can display, is an important specification, but you'll find very little useful information about it in product sheets from most manufacturers. That's because there's no single set way to measure contrast — and there's plenty of jiggle room in the methods that manufacturers do employ, which can be used to inflate ratings. Most companies record contrast ratio using a full on/off measurement that uses black/white test patterns — a method that results in generally bloated numbers. A few others use a black-and-white checkerboard pattern (ANSI contrast) that more closely represents regular program material. The contrast-ratio ratings that this type of test generates tend to be much lower, but they more accurately reflect how the TV will perform in real-world situations.

Soundproofing Options

Q. My house has an unfinished basement, and I would like to soundproof it (okay, my wife would like me to). I know insulation companies make rolled insulation that can be used for this, but is this the best way? I have a large basement, so the expensive stuff might be a bit out of my league. I will probably drywall the ceiling eventually, although I haven't completely ruled out a drop-ceiling. What are my best options?
Greg Madama
Cleveland, OH

A. Ian G. Masters says: The rolled insulation you're thinking of can be quite effective in dealing with high frequencies, and I imagine that the basic, inexpensive sort would do as well as the more exotic variety. You may not need it, however, as most floors and walls are quite good at blocking sounds in this range. Where you're likely to get leakage is up the stairs (adding a door at the top helps) and through heating ducts and other gaps, where the insulation could be of use. Bass is another matter. Because of the large wavelengths involved, absorption of the sort you suggest is ineffective. Mass is the only thing that works, so forget the drop ceiling and go for the dry-wall — preferably, several thicknesses of it.

Overscan Blues

Q. My rear-projection HDTV has an overscan problem. When I watch high-definition baseball games, the scoreboard gets cut off. Also, on regular TV the heads get cut off. Anything I can do to correct it?
Richard Taddonio
Brooklyn, NY

A. Al Griffin says: Overscan, or the amount of picture area that gets hidden behind a TV's screen, is typically set by the manufacturer at around 4% or less — a level that shouldn't interfere with onscreen graphics, heads, or anything else that falls within the "TV Safe" area of the image as monitored by the broadcaster. But it sounds as though your TV is set to the wrong display mode (aspect ratio), such as zoom, or suffers from abnormally high overscan. Try selecting the TV's various display modes to see if that solves the problem. If not, you may be able to have its overscan adjusted by a trained technician. Check with the manufacturer for a local service center. You could also contact the Imaging Science Foundation (www.imagingscience.com) to see if there's a qualified technician in your area to tackle the job.

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