Their outcomes were published on Thursday in Scientific Reports. The model is not yet the most useful gadget in real world conditions, but it points the way toward the development of technologies that may help relieve the strain of noisy city living.
Loaning from the very same technological concepts utilized in noise-canceling headphones, the group broadened the principle to fit an entire space by placing 24 small speakers in a window. The speakers emit sound waves that correspond to the inbound racket and neutralize it– or, at least some of it.
Unfortunately, human voices do not fit within most of that variety. Among the next difficulties will be to discover a way to silence loud discussions from across the method.
Another limitation is that the system is bad at neutralizing sporadic sounds, like firecrackers, cars and truck horns or the occasional blaring crash of metal shop shutters– the type of sounds that drive many New Yorkers to slam their windows shut.
One reason for the restriction on frequency is the size of the speakers. To counteract lower frequencies would require bigger bass speakers. Those would interfere with ventilation and your capability to see through the window.
Its a trade-off, and one option may be setting up bigger windows, or discovering a way to make it work with smaller sized speakers.
As it is, the 24 speakers, each about 2 inches in diameter, are a little bit of an aesthetic limitation.
“One complaint that we get is that its unsightly,” Dr. Lam stated.
If it can neutralize the noise of the jet taking off from Runway 13 at LaGuardia, that is (soft) music to the ears.
The system is based on the frequency of the acoustic waves and, for now, the optimum variety is in between 300 and 1,000 hertz.
In Singapore, a city near the Equator where temperature levels are frequently high, overlapping transportation systems and the desire for natural ventilation in modern-day high-rise house towers can pose a healthy-living dilemma.
Vehicle alarms, jackhammers, an inebriated argument and the rumble of the No. 7 train passing overhead. It is the wonderful urban symphony that pours into a normal New York City apartment day and night.
Sure, closing the window can help, but there goes your natural ventilation.
What if there were technology to cancel the upseting shout, like a pair of giant noise-canceling earphones for your apartment?
Researchers in Singapore have established an apparatus that can be put in a window to minimize incoming noise by 10 decibels. The system was created by a team of scientists, including Masaharu Nishimura, who developed the basic principle, and Bhan Lam, a researcher at Nanyang Technological University in Singapore.
” I grew up in Singapore,” Dr. Lam said in a Zoom interview from his home there. “Its a small city with a lot of sound, so I have some motivation to resolve this problem.”
Dr. Lam explained that “in places like Singapore, we desire to keep the windows open as much as possible” to reduce using carbon-intensive air-conditioners and to avoid accumulation of stale air that can pose health dangers for some people.
With windows open, the constant din from city traffic, trains, jets passing overhead and building and construction equipment can rattle apartments. The Anti-Noise Control Window, as it is called, is the sonic equivalent of shutting a window.
With any noise, the best way to reduce it is at the source, like a weapons silencer. So the scientists dealt with the window aperture itself as the noise source, due to the fact that most noise enters a space that way.
The system uses a microphone outside the window to detect the duplicating noise waves of the upseting noise source, which is signed up by a computer system controller. That in turn analyzes the proper wave frequency required to neutralize the sound, which is transferred to the range of speakers on the inside of the window frame.
The speakers then emit the correct “anti” waves, which counteract the inbound waves, and there you have it: near blissful silence.
“If you being in the space, you get that very same feeling like when you snap on the switch of noise-canceling earphones,” Dr. Lam stated, splaying his hands to represent the relaxing result.
The system is best at attenuating the audible blasts from the kinds of steady sound sources found within the ideal frequency range.
