Sky-high Wi-Fi

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Date:30 April 2008 Tags:, , , , ,

Q I’ve heard that some airlines are rolling out Wi-Fi on their planes. How does this work, and wouldn’t the radio interfere with the navigation equipment?

A There are two ways an Internet connection can be beamed to a moving aircraft, neither of which uses Wi-Fi for anything other than linking the connection to the Web-enabled devices inside the plane. The first is an “air-to-ground” system, which essentially broadcasts a radio connection from ground-based towers to receivers on the aircraft. Aircell, which uses similar technology to connect those rarely used tray-table telephones, plans to use this method to build an in-flight Internet service delivered over recently purchased radio spectrum. American Airlines has already signed up.

Of course, a system that relies on ground towers won’t work for transoceanic flights, meaning that many international flights require satellites. Several airlines are looking atsatellite-based Internet connections, which would be delivered to dishes, much like the live television feeds available on most JetBlue and Delta flights.

As for the threat of radio-enabled gadgets causing interference with avionics, it’s a matter of debate (one we explored in more detail in Digital Clinic back in June 2006). In short, while it’s possible that Wi-Fi and other radio signals might interfere with onboard equipment, there are no reliable reports from the US Federal Aviation Administration to suggest that it’s a real problem.

Still, to be safe, the airlines ask you to turn off all electrical devices during takeoff and landing, when aircraft are most reliant on their own electronic systems and have the most exposure to potential interference from on-ground ones.

Sound effects
Q
My equaliser has separate settings for rock, jazz and classical. Who decides on these settings and why do they make a difference?

A“Audio is subjective,” says Alan Kraemer, chief technology officer at SRS Labs, one of the companies behind these genre-based presets. “There are criteria you can use, but it’s still ultimately up to the individual tastes of the engineer.”

That’s not to say that equaliser settings are completely random. Certain types of music naturally lend themselves to different frequency mixes. For example, hip-hop demands a powerful bass, but other genres are a bit more complicated. “It gets more subtle for things like jazz,” Kraemer says. “Bass is the root of jazz and anchors the rhythm, but you also have a lot of high-frequency information like the hi-hats on the drumkits that you want to bring out. So you bring the low end up a little bit and the high end up a little bit, like a smiley curve.”

Classical music is the easiest: “You pretty much want to do nothing. You just leave it alone.”

In short, equaliser pre-sets are all a bit of a lucky dip and are often handed down from one group of engineers to another as a set of general guidelines. So don’t be afraid to dial in your own settings. You may be just as qualified, and there’s nobody who has a better understanding of what sounds good to you.

Another dimension
Q
My Samsung DLP TV is supposed to be 3D-capable, but I can’t find any DVDs that are in 3D. Is there any 3D content out there, and how can I get it?

AMost of Samsung’s latest DLP-HDTVs (and a few of the company’s plasmas) are “3D-capable” – albeit with the use of special 3D goggles. But the selection of movie content is a bit slim for now. That’s because movies originally filmed in 2D need to undergo time-consuming, frame-by-frame conversion to look their best in 3D. Even then, they still won’t pop from the screen as well as a film that was originally shot in 3D (which typically requires two cameras shooting simultaneously from slightly different angles).

Samsung has partnered with Dynamic Digital Depth (DDD) to provide 3D goggles in an optional kit (available in the US for about R1 500) that also includes a computer program for converting regular DVDs into 3D. But because it uses software-based algorithms to simulate the effect, the converted films don’t look nearly as good as movies that were natively shot in 3D. The program requires you to use a PC for now, but DDD is currently developing TVs with the technology built in.

Still, there’s another reason that it may be worth connecting a PC to your 3D-capable TV: a growing number of 3D-enabled games (including Madden 08 Football and The Sims 2) and programs (including Google Earth) can easily be displayed on your HDTV via a PC link. And some of them really do pop.

Bar tending
Q
I want to avoid cluttering my living room with speakers. I love the idea of these new sound bars, but have no idea how they sound or where to place them.

AAlthough no sound bar can perfectly emulate a properly tuned 5.1-channel surround-sound system, many of them do a surprisingly solid job. Sound bars generally integrate an amplifier and an array of speakers – from just over a dozen to nearly 50 – into a single bar. By delaying certain sound waves, they can create the illusion of multi-channel audio coming from different parts of the room at the same time. Some of them, such as the popular sound bars from Yamaha, increase their effect by bouncing sound waves off walls, so be sure to consider the layout of your home theatre if you’re considering one of these devices. (They work best in enclosed rooms because sound gets lost in open spaces.)

Fortunately, placing the sound bar is a piece of cake: just put it under your TV. Many sound bars include a small microphone that you hold in front of your seating position to calibrate the delay. By sending out test waves and listening to the responses that come through the microphone, the speakers figure out the perfect mix of delays needed to maximise the surround-sound experience, no matter where you keep your couch in the room.

One caveat: the spakers used in sound bars tend to be on the small side, making their reproduction of lower frequencies somewhat spotty. Audio experts suggest rounding out the sound by adding a subwoofer. Fortunately, a subwoofer can provide decent bass from just about anywhere in the room, so it’s an easy improvement.

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