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Tips for buying web and video phones

Telephone operators of yore would be puzzled by people nowadays, placing calls with headsets and using web cams to send videos around the globe.

india Updated: Sep 03, 2007 10:52 IST

Telephone operators of yore would be puzzled by people nowadays, placing calls with headsets and using web cams to send videos around the globe. And that's just for starters.

In the 21st century, it's not unusual to see people using instant messenger programmes to communicate worldwide.

But, confused as they might be by today's web cams, they might still be able to teach us a trick or two when it comes to choosing a headset.

Headsets come in over-ear and inner-ear model versions, which are further subdivided into monaural and binaural versions. Monaural transmit sound into only one ear while binaural versions carry sound into both.

"In our laboratories, the monaural systems perform better than the binaural systems," says Dieter Lorenz, a professor who tests headsets at the Giessen-Friedberg Technical College.

Lorenz's studies have found ear buds and other inner ear devices do not match full headsets, either in terms of comfort or audio quality.

For one thing, inner ear models usually don't reproduce voices as well as they can be ill-fitting. The quality of voice reproduction usually depends on the headset's frequency spectrum and frequency response. More expensive professional headsets starting at 100 euros ($136) can key in on frequencies between 300 and 8,500 Hertz, which makes them better at filtering human voices out of background noises.

Padding material also affects sound quality. Foam padding can dampen sound while leather or artificial leather pads can reflect and strengthen sounds.

It's not clear why monaural headsets reproduce human voices better than binaural versions. Although studies have shown that most people's ears hear equally well, most people usually have a "telephone ear," which most feel hears better than the other.

Lorenz recommends binaural headsets only in areas with a lot of noise distractions, like a call centre. "But then you should take elocution training to speak at the right volume," he says. That's because people regulate their volume based on the sound being pumped into their ears.

When purchasing a headset, it's important to make sure the headband is easy to adjust, advises Lorenz. Earpieces should fit easily. The microphone should also be adjustable, even in its length. There shouldn't be so much earpiece padding that air can't reach the ears. It is important that the headset is comfortable after hours of wear, so try out different models.

People who want to see their conversation partners during calls will need a web cam for video telephoning. The standard remains a VGA resolution of 640 by 480 pixels 0.3 mega pixels with a refresh rate of 30 frames per second.

"That's perfectly adequate for making video calls," says Mark Palkow of the Berlin-based Society for Digital Audiovisual Communication (daViKo), which produces video conference software. "No software can carry more, since the information has to go over the Internet," he adds.

As most Internet connections have limited bandwidth, many messenger programmes do not even send VGA resolution images. Software for a live web video conference has to make compromises between resolution, picture refresh rate and computer power to transmit the individual pictures, says c't, a Stuttgart-based computer magazine.

Web cams vary greatly in model and price. "We recommend web cams starting at 50 euros," says Palkow. Anyone with a digital camera or a camcorder can check if their device also has a web cam mode.