Physicists Generated Sound Waves That Travel In One Direction Only (sciencealert.com) 9
An anonymous reader quotes a report from ScienceAlert: Imagine three people huddled in a circle so when one speaks, only one other hears. Scientists have created a device that works like that, ensuring sound waves ripple in one direction only. The device, developed by scientists at ETH Zurich and the Swiss Federal Institute of Technology Lausanne, is made up of a disk-shaped cavity with three equally-spaced ports that can each send or receive sound. In an inactive state, sound transmitted from port 1 is audible to ports 2 and 3 at equal volumes. Sound waves bounce back to port 1 as an echo as well. When the system is running, however, only port 2 hears port 1's sounds.
The trick is to blow swirling air into the cavity at a specific speed and intensity, which allows the sound waves to synchronize in a repeating pattern. That not only guides the sound waves in a single direction, but gives more energy to those oscillations so they don't dissipate. It's kind of like a roundabout for sound. The scientists say their technique may inform the design of future communications technologies. New metamaterials could be made to manipulate not just sound waves but potentially electromagnetic waves too. "This concept of loss-compensated non-reciprocal wave propagation is, in our view, an important result that can also be transferred to other systems," says senior researcher Nicolas Noiray. The research was published in the journal Nature Communications.
The trick is to blow swirling air into the cavity at a specific speed and intensity, which allows the sound waves to synchronize in a repeating pattern. That not only guides the sound waves in a single direction, but gives more energy to those oscillations so they don't dissipate. It's kind of like a roundabout for sound. The scientists say their technique may inform the design of future communications technologies. New metamaterials could be made to manipulate not just sound waves but potentially electromagnetic waves too. "This concept of loss-compensated non-reciprocal wave propagation is, in our view, an important result that can also be transferred to other systems," says senior researcher Nicolas Noiray. The research was published in the journal Nature Communications.
This was done years ago (Score:1)
Just like talking to my ex. She would talk but couldn't hear anything.
Re: (Score:2)
This has already been done for RF energy. They are called Port Circulators. They allow a common antenna to be connected to both the transmitter and receiver sections of a radio/radar set without the transmitted signal overwhelming the receiver.
RF Circulators [pasternack.com]
Prior Art (Score:2)
Re: (Score:2)
Sorry about that, Chief!
Gilding the lily. (Score:2)
just set Linedef to block sound! (Score:2)
just set Linedef to block sound!
Where have I seen this before...? (Score:2)
I encourage people to watch the Better Off Ted [wikipedia.org] episode Bioshuffle [fandom.com] (s1e9) and the bits with their hypersonic sound emitter -- aka "The Voice of God."
Ted: So, what is it? ...
Phil: We call it "The voice of God"
Ted: No, we don't.
Lem: Hypersonic Sound, or H.S.S... projects a narrow beam of sound which can only be heard by a specifically targeted person. Field testing shows that the subject - or victim as I like to call people helped by Veridian technology - can be hundreds of feet away and will hear the message as though it's being whispered only to them.
Phil: At full power, the sound wave is so intense, it can cause vomiting. [foreshadowing]
Re: Where have I seen this before...? (Score:2)
Just the description reminded me of these... (Score:1)