Directional sound allows you to listen to whatever you want. 00:48, June 19, 2007 Beijing News
Directional ultrasonic waves are mixed with air and converted into audible sound for the human ear
When you were walking around in a quiet food store and passing an aisle, a voice suddenly sounded in your ears: "Are you thirsty? Buy a bottle of drink." So, you stopped in front of the drink rack, but you There was no one else around, and the salesperson a meter or two away didn't seem to hear anything. What's going on? This is the magic of directional sound generators. If a traditional speaker emits sound in all directions like a light bulb emits light, then a directional sound emitter is similar to a spotlight, emitting a beam of sound waves that propagates in a directional direction.
The sound generator is only half an inch thick
The sound waves are made of ultrasonic waves. This ultrasonic sounder is only half an inch thick and is driven by an amplifier. The amplifier sends voltage to the metal polymer film of the sounder, causing the film to vibrate at a frequency of 60,000 Hz or higher to generate ultrasonic waves. In the air, the density of uniform ultrasonic waves fluctuates, and the ultrasonic waves change and become sounds that can be heard by the human ear. The principle and technology of this kind of directional ultrasonic sound generation are not very difficult. Engineers can make a beam of ultrasonic waves send human voices, music, or even any sound you can understand. When you hear a voice directing you to buy a drink in a grocery store, it's because you're standing inside this cylinder of sound waves.
In November 2006, the American TV Court began to use audio spotlights in some large bookstores to promote the book version of the newly launched TV series "The Murderer". When a wandering customer accidentally walked near a poster for the product, a mysterious voice rang in his ears: "Hey, come here, don't turn your face. Do you hear my voice?" Have you ever thought about being a murderer? Have you ever thought about committing a heinous crime? I have always thought about it. I am a writer who specializes in best-selling crime novels..."
The price is too high. Impact Promotion
As early as the 1960s, military and sonar researchers tried to exploit the principles of this phenomenon, but could only produce highly distorted sound signals. In 1998, Joseph Pompeo proposed a method that greatly reduced distortion. Later, he designed an amplifier, some electronics, and speakers to produce ultrasonic waves that, according to Pompeo, were so "pure" that they produced clear sound. He registered the trademark name AudioSpotlight for this technology, and founded Holosonics.Inc., a comprehensive applied acoustics company in Watertown, Massachusetts, USA in 1999.
Pompeo's loudspeakers are installed in the lobby of Omni Acoustics and have been toured in places such as the Museum of Fine Arts in Boston and the Epcot Center at Walt Disney World. No noise is added to these rooms when visitors stand in front of exhibits or television screens while docents explain. Some department stores are already preparing to arrange some retail exhibitions, and car manufacturers are also gearing up to use these products so that passengers can only hear the music they like.
In your living room, a speaker on a tilt stand allows Dad to hear the sound from the TV while the rest of the family sits on the sofa reading quietly without being affected.
The main obstacle to bringing directional sounders to the masses is still the high cost: the current cost of some products is estimated to be between US$600 and US$1,000, or even higher. If the price bottleneck is overcome, users may experience its "fun" in the near future and be willing to spend money to purchase it.
"Scientific American" Chinese version of "Global Science" magazine feed
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Hearing frequencies of various animals
Animals and sound frequencies that humans can hear: Some animals can hear ultrasonic noise in directional sound waves. These ultrasonic generators emit frequencies from 10,000 to 80,000 Hz.
The frequency of sound waves that humans can hear is between 10,000 and 20,000 Hz. Dogs can hear sound waves at around 10,000 Hz, rats can hear sounds up to 90,000 Hz, and bats, dolphins and great beluga whales can hear sound waves at 100,000 Hz and higher.
Because of the existence of middle ear bones, humans can only hear sound waves with frequencies below 20,000 Hz. But in the experiment, the researchers applied ultrasound waves with frequencies as high as 100,000 Hz to the skulls of some subjects, and some people reported "hearing" sounds.
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Ultrasonic sound directional system
2004-2-3 17:55:26 Excerpted from "Abroad Science and Technology Trends" Read 174 times
Honor: Best Science and Technology in General Category
Woody Noyce, CEO of an American technology company, invented this system called Ultrasonic Orientation System (HyperSonic) Sound System) device can be regarded as the most breakthrough invention in the field of acoustics since the invention of the speaker. Its most outstanding feature is the directional transmission without distortion of the sound, the sound field does not spread, and the longest propagation distance can reach 137 meters, which is similar to the "sound transmission from thousands of miles" and "sound transmission into the secret" in martial arts novels. The kung fu is very similar.
Sound usually spreads in all directions. Ultrasonic directional technology converts sound waves into highly directional ultrasonic waves, which are then transformed by instruments and restored to natural sounds in the receiver's ears.
Let the sound be transmitted in a directional manner (2008-02-25 23:50:30)
Tag: Military Category: Brainwave Instrument
Let the sound be directionally transmitted
Mark Fischetti
Written by Mark Fischetti
Translated by Zhan Hao
Dang You were wandering around a quiet food store, and when you passed an aisle, a voice suddenly sounded in your ears: "Are you thirsty? Buy a bottle of drink." So, you stopped in front of the drink rack, but there was no one beside you. There was no one else around, and the salesperson a meter or two away didn't seem to hear anything. What's going on?
It seems simple: you happened to be standing inside a sonic cylinder at the time. If a speaker emits sound like a light bulb emits light in all directions, then a directional generator is similar to a spotlight, emitting a beam of sound waves. This sound wave is composed of ultrasonic waves. Under normal circumstances, humans cannot hear ultrasonic waves, but when the ultrasonic waves interact with the air, they can emit sounds audible to the human ear. The ultrasonic sound generator is only half an inch thick and consists of Driven by an amplifier, the amplifier sends voltage to the metal polymer film of the sound generator, causing the film to vibrate at a frequency of 60,000 Hz or higher to generate ultrasonic waves. In the air, the density of uniform ultrasonic waves fluctuates, and the ultrasonic waves change and become sounds that can be heard by the human ear. The principle and technology of this kind of directional ultrasonic sound generation are not very difficult. Engineers can make a beam of ultrasonic waves send human voices, music, or even any kind of sound.
As early as the 1960s, military and sonar researchers tried to exploit the principles of this phenomenon, but could only produce highly distorted sound signals. In 1998, Joseph Pompei (then still working at MIT) proposed a method that could greatly reduce distortion. Later, he designed an amplifier, some electronics, and speakers to produce ultrasonic waves that, according to Pompeo, were so "pure" that they produced clear sound. He registered the trademark name AudioSpotlight for this technology and founded Holosonics Inc. in Watertown, Massachusetts, in 1999.
Pompeo's rival, inventor Woody Norris's American Technology Company, has also launched a corresponding product - HyperSonic Sound.
Pompe’s loudspeakers are installed in the lobby of All Applied Acoustics and are on tour at venues such as the Museum of Fine Arts in Boston and Walt Disney World’s Epcot Center. No noise is added to these rooms when visitors stand in front of exhibits or television screens while docents explain. Some department stores are already preparing to arrange some retail exhibitions, and car manufacturers are also gearing up to use these products so that passengers can only hear the music they like. In the living room, the speakers on the tilt stand allow Dad to hear the sound from the TV alone, while other family members sit on the sofa and read quietly without being affected.
There are also objections. They believe that in some cases, headphones have similar functions, and this device also has some shortcomings. For example, car seats will reflect sound waves, often causing echo. However, the main obstacle to bringing directional sounders to the masses is their high cost: some products cost between US$600 and US$1,000, or even more. If the price can come down, users might consider buying a directional sounder...or come across it while shopping. /s/blog_4b72aa9d01008fp5.html