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Have you ever been indiscriminately bothered by square dance music or campus radio announcements? Have you ever imagined sound traveling in a direction like a flashlight beam? With breakthroughs in acoustic technology, directional sound technology is making this a reality. How does this "sound sniping" technique work? And how will it reshape our lives?
The "laser pointer" of sound: Unveiling the principle of directional sound generation
Unlike the "splashing" diffusion of traditional audio equipment, directional sound technology allows sound waves to propagate in a straight line. The core technologies fall into two categories:
1. Ultrasonic carrier wave technology
By utilizing the high directivity and nonlinear effect of ultrasound, audible sound signals are modulated onto an ultrasonic carrier wave and then transmitted directionally through a transducer array.
2. Beamforming technology
Based on array signal processing, the sound waves from multiple loudspeakers are delayed and weighted, causing them to superimpose in space to form a directional sound beam.
This technology, derived from military sonar, is becoming a new tool for solving noise pollution:
Public Spaces: By confining square dance music to the dance floor area, the surrounding residential areas have regained their tranquility.
Educational Scenario: The playground broadcast system no longer interferes with the teaching buildings, achieving a balance between "lively activity areas and tranquil quiet areas."
Traffic management: Highway warning sounds are transmitted directly to the driver's seat, avoiding interference from environmental noise.
Cultural exhibitions: Each exhibit features independent audio narration, eliminating the reverberation of sound throughout the exhibition hall.
An extension of military technology: the "invisible blade" of directional sound waves.
LRAD long-range acoustic device: It can emit 145 decibels of focused sound waves (equivalent to the noise of a jet aircraft taking off) from 2500 meters away, forming a "sound wall" only in a specific direction.
Sonic sniper system: Identifies heartbeat characteristics in darkness at a distance of 50 meters by reflecting sound waves at the millimeter level.
Targeted communication: Enabling the transmission of encrypted messages within 500 meters, audible only to the target, in special operations.
Inspiration from Nature: Masters of Biodirectional Acoustics
Such technologies have long been pioneered in nature:
Bats: Emits a narrow-angle ultrasonic beam at 15-20 degrees (approaching the accuracy of military sonar), capable of detecting obstacles as thin as 0.05mm.
Toothed whales (such as dolphins): use a "melon organ" on their forehead to switch between 200kHz positioning waves and 20kHz communication waves.
Reshaping the Urban Soundscape: From Noise Reduction to Sound Rights
Directional sound products from companies like Sanyuan Environment are driving the practical application of technology: when pedestrians enter a specific area, the device automatically triggers customized sound effects, and different areas can simultaneously play independent content. This intelligent soundscape management provides an innovative solution to urban problems such as noise from square dancing.
Noise pollution is a persistent problem in modern cities. The World Health Organization points out that long-term exposure to noise levels above 55 decibels significantly increases the risk of cardiovascular disease. The revolutionary aspect of directional sound technology lies not only in "noise reduction" but also in reconstructing the spatial ownership of sound-making sound clearly audible in areas that need it, while protecting quiet areas from disturbance.
Technological Revelation:
As sound transforms from a disorderly intruder into a precisely controllable urban element, we are witnessing an evolution of acoustic civilization-empowered by technology, public spaces will achieve the ideal scenario of "vibrant where it should be noisy, and silent where it should be quiet."