NXT has a sister company Mission that has delivered the most
acclaimed Mission M Cube partially based on NXT technology -see our article.
They combined efforts again to produces the first NXT-licensed product for
the U.S. market due by mid-August, consisting of a pair of 12x1 x1-in.
wall flat panels and a 10-in. powered subwoofer.
The company claims that their technology is "scalable from credit-card
size
to
120-sq.-meter
cinema
screens". The only difference is the bass performance, i.e. the larger the
better when it comes to bass performance.
The multimedia speaker is a prime target for both NXT and Harman International,
which is the US
licensor for NXT.
Laptop PCs already use this technology, like the NEC model
PC-9821. The 0.5mm flat-panel speakers slip behind the PC's screen
when they're not in use, and deliver a sound that beats most laptop speakers.
But there are other applications as well in the desktop PC and PDA world. Talking
posters and banners,
public
address
systems
and car audio speaker
systems are candidates too (UK carmaker TVR has chosen NXT's AFR tehnology that
combines
conventional driver for low frequency and DML panel for mid-to-high
frequency in one single unit. While NXT sets
its
sights
on
future
applications
for
flat-panel
speakers, several companies that have various patent swaps and cross-licensing
agreements
with NXT–including Sound Advance Systems, Fostex and Noise Cancellation
Technologies Inc. (NCT)–are delivering their own versions of flat speakers
in the United States. The NXT Exciter Assembly will make any material sing, though
getting very low bass is definitely a problem.
DML (Distributed Mode Loudspeakers, yes, those are what we described for the
Mission M-Cube system)
technology
is NXT's
flat
speakers
flagship for home audio systems. To understand... forget what you know about
conventional speaker systems, even if the amplifier-to-loudspeaker connection
is still valid here. But that's where comparison comes to an end: No woofer,
tweeter, crossover. Just a magnet, a voice coil and a panel (think of a
Japanese paper wall).
Here the magnet-and-coil assembly moves a microscopic 40 microns, which gently "shakes" the panel, starting a series of bending waves that go in all directions.
"You end up with these bending waves that are now crossing at every angle and at different speeds," says Jon Vizor, director of marketing for NXT. "And it becomes this chaotic mass of crossing bending waves that form the modes that produce the music."
Although NXT operates in a different sphere, its goal is that of conventional speaker design: to simply reproduce the audio signal as faithfully as possible.
"At one extreme, you're trying to design a transducer that's as nonresonant as possible," says Dr. Floyd Toole, vice president of engineering at Harman International, licensor of NXT technology in the United States. "At the other extreme, you have a system that in its ideal form is nothing but resonance. And there are so many resonances and they're so densely packed together in the frequency domain that no one of them stands out as being discretely audible as a source of unwanted coloration. What you hear is a facsimile of what you should be hearing."
Because the radiation of sound waves from an NXT panel is so diffuse, the speakers don't create a sweet spot--that perfect listening position between the speakers where imaging and sound stage are defined in the conventional speaker world. For that reason, flat-panel speakers will probably never make it in audiophile circles. But there are plenty of applications where the diffuse soundfield makes sense, both in and outside of the home. Since there's no beaming of sound from a single point source, you can easily walk around a room where flat-panel speakers are playing and not hear a variation in volume or timbre. That could play well in multiroom audio and home theater systems, and the possibilities in large public spaces are endless. Imagine a ceiling-tile speaker that could cover a much broader area and deliver much better intelligibility than a conventional speaker.
see www.nxtsound.com
Flat speakers can make home theater look and fit a lot better in your home.
GEKKO SPEAKER PANELS
The NXT Exciter Assembly will make any material sing, though getting very low
bass is definitely a problem.
According to Dave Claybaugh, vice president of NCT Audio Products Inc., his
company and NXT are both trying to create the same result but are going about
it differently. NCT uses a cool-running piezoelectric driver, rather than a
magnet and voice coil, to induce vibrations in its panel. Also, NCT is shooting
for a minimum flat-panel stand-alone low-end response of 100Hz, rather than
the 200Hz NXT has promoted, Claybaugh says. In order to achieve that level
and to come to market first, NCT cobbled together a hybrid design using a flat
panel and a traditional cone driver to handle the midbass frequencies. Its
Gekko system also includes a separate 10-in., 65-watt subwoofer. "We ran
into a lot of the same challenges that NXT has run into," Claybaugh says.
A primary challenge has been to design small drivers that can handle a lot
of power–enough to produce high-quality, full-bandwidth sound. But he's
bullish on the prospect of a true, full-range flat-panel speaker. "An
all-flat-panel speaker is absolutely feasible," he says. "But it
will probably be a couple of years before we see an all-panel speaker alone."