Speech jammers were a meme a little while back. By feeding back delayed voice audio to a person’s ears, it makes it near-impossible for most people to speak, as our speech system runs on a continual feedback loop. [Benn Jordan] decided to try reworking that concept by replacing headphones with a directed sound projector.
The key to the project is the use of hypersonic sound arrays. These essentially use high-frequency sound beyond the human range of hearing to carry a lower-frequency sound signal. By essentially modulating this higher-frequency carrier to create the perception of lower-frequency sound, it’s possible to create an audible signal that is highly directional. It’s like a “sound laser” that can be pointed directly at a person to allow them to hear it, which is then inaudible when pointed slightly away.
These allow the delayed voice signal to be fired at a person’s head with a relatively narrow spatial spread. When an individual speaks into a microphone hooked up to the device, delayed audio is sent through the hypersonic array back to the speaker’s ears, garbling their speech as their brain gets confused by the feedback.
[Benn] demonstrated the device in public by offering random individuals $100 to read a paragraph out of a book. The speech jammer worked a treat, and [Benn] was able to keep his money… until one amazingly immune individual breezed through the test. Check out our prior coverage of speech jamming technology. Video after the break.
[Thanks to Hyperific for the tip!]
Source : https://hackaday.com/2023/10/01/hypersonic-speech-jammer-works-at-a-distance/