A pair of Japanese researchers have come up with a device that they call the SpeechJammer. It is reportedly able to stop people from talking from a distance, without any physical effects on the person being silenced.
The ‘gun’ that does all the work is composed of a directional microphone, a direction sensitive loudspeaker, distance sensor and laser pointer. It functions by recording a person speaking and directing that speech back to the original speaker with a fraction of a second’s delay. The resulting effect, known as Delayed Auditory Feedback (DAF), can make it almost impossible for the speaker to continue.
Researchers Kazutaka Kurihara and Koji Tsukada have found that the SpeechJammer has less effect on constant monotonous sounds and that it is more likely to disrupt certain types of speech.
“This effect can disturb people without any physical discomfort, and disappears immediately [after] the speaking stops. Furthermore, this effect does not involve anyone but the speaker. It is expected that the negative aspects of speech…can be relaxed by the ability to jam remote people’s speech.”
Source: DigitalTrends