It’s Hard to See What London-Based Speaker Maker NXT Plans to Do Next

LONDON — In a twist to the Victorian adage about well-behaved children, a British high-technology firm has developed a loudspeaker that can be heard, but not seen.

NXT PLC says its transparent speakers--glass or plexiglass panels that emit sound through subtle vibrations--rival conventional speakers in quality.

The panel speakers are much less bulky than conical speakers, so the new technology should allow for further miniaturization of electronic devices like laptop computers and televisions, the company says.

See-through speakers could, in theory, be as large as movie screens and small enough to fit on a business card. Refinements in the technology might even enable a car windshield to double as a stereo speaker.

“You can let your imagination run wild. You don’t have to think of these oblong boxes,” said Jon Vizor, NXT’s marketing director.

NXT predicts that the first products containing transparent speakers could hit the market within 18 months. They are likely to be laptops, televisions and home-theater systems.

The transparent speakers are triggered by an electronic “exciter” the size and shape of a quarter that is attached to the edge of the speaker panel. The exciter emits an impulse that causes the panel to vibrate, and the vibrations, which are invisible to the human eye, create sound waves.

Unlike conventional loudspeakers, which contain a diaphragm that moves back and forth like a piston, different parts of the transparent speaker panel vibrate independently. The panel, or screen, ripples in a complex pattern that seems almost random.

Under strong magnification, the speaker surface resembles a three-dimensional map of mountainous terrain, with each peak punching the air to help create sound waves.

“It’s like hundreds and hundreds of minuscule volcanoes erupting all over the screen,” Vizor said.

NXT says its see-through speakers have a wider frequency than conventional ones, giving them a deeper bass and a less tinny sound. And they project sound in all directions at once, making it unnecessary, for example, for an audiophile to face a stereo speaker to hear music at its clearest.

Headquartered in London, the 3-year-old company based its research on work its scientists originally did to reduce cockpit noise in jet aircraft for Britain’s Defense Ministry.

“Its quite a novel technology,” says Matthew Alleyne, a technology reporter for the Electronics Times--a London-based weekly newspaper that covers Britain’s electronics industry. “I would say it’s fairly revolutionary.”

So revolutionary, in fact, that some electronics industry watchers aren’t even aware of it.

“If it’s space-saving and weight-saving, that sounds like great stuff,” said Tom Wills-Sandford of the Federation of the Electronics Industry, a British trade association.

NXT used similar technology to develop an opaque speaker panel two years ago. Some 90 firms, from NEC Corp. in Japan to Philips Electronics N.V. in the Netherlands, have paid for licenses to that technology.

Opaque panels are already available on a wide array of electronics goods, including personal computers and portable CD players. U.S. audio companies licensed for the technology include Harman International Industries Inc., maker of JBL and Infinity speakers, and Alpine Electronics Research Inc.

Wharfedale International Ltd, a firm based 60 miles north of London in Huntingdon, uses NXT’s technology to make an opaque speaker camouflaged as a ceiling tile.

It also markets a speaker designed as a framed picture, for use in homes, hotels or restaurants. Customers can paint or decorate the white speaker panel however they like.

As for transparent speakers, Vizor says the technology for them is still so new that NXT has yet to start selling licenses for it.

Peerless Fabrikkerne A/S, a Danish company that makes the exciters for speakers using NXT’s technology, is trying to develop its own type of transparent speakers.

Company president Nils Erik Kristensen, speaking from Copenhagen, acknowledged NXT’s lead in the see-through technology race. But he suggested that competition in transparent speakers may not be far off.

“It’s certainly something that a lot of companies are looking at,” he said.