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Hardware Idle Science

Speech-Jamming Gun Silences From 30 Meters 370

MrSeb writes "Japanese researchers have created a hand-held gun that can jam the words of speakers who are more than 30 meters (100ft) away. The gun has two purposes, according to the researchers: At its most basic, this gun could be used in libraries and other quiet spaces to stop people from speaking — but its second application is a lot more chilling. The researchers were looking for a way to stop 'louder, stronger' voices from saying more than their fair share in conversation. The paper reads: 'We have to establish and obey rules for proper turn-taking when speaking. However, some people tend to lengthen their turns or deliberately interrupt other people when it is their turn in order to establish their presence rather than achieve more fruitful discussions. Furthermore, some people tend to jeer at speakers to invalidate their speech.' In other words, this speech-jamming gun was built to enforce 'proper' conversations."
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Speech-Jamming Gun Silences From 30 Meters

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  • Umm (Score:4, Interesting)

    by TheSpoom ( 715771 ) <> on Thursday March 01, 2012 @12:02PM (#39209407) Homepage Journal

    So, here's the technical implementation:

    The gun works by listening in with a directional microphone, and then, after a short delay of around 0.2 seconds, playing it back with a directional speaker. This triggers an effect that psychologists call Delayed Auditory Feedback (DAF), which has long been known to interrupt your speech (you might’ve experienced the same effect if you’ve ever heard your own voice echoing through Skype or another voice comms program). According to the researchers, DAF doesn’t cause physical discomfort, but the fact that you’re unable to talk is obviously quite stressful.

    What's to prevent someone from simply speaking louder to talk over the "jammer"? Why wouldn't this be the target's first reaction? Wouldn't a delay of 0.2 seconds sound just like an echo?

    There's also the fact that this is highly targeted (no shutting up entire audiences) and doesn't actually create "silence", just cacophony.

  • Re:Umm (Score:5, Interesting)

    by MickyTheIdiot ( 1032226 ) on Thursday March 01, 2012 @12:11PM (#39209581) Homepage Journal

    Having worked with different types of audio equipment my entire life I can assure you that this effect is real.

    However, depending on the delay it might not "shut you up" completely. It can make you slur or not be able to form words. You can get stuck on a single syllable because your brain says you haven't finished it.

    So, no, it doesn't sound just like simple feedback or echo.

  • Re:Umm (Score:5, Interesting)

    by Aladrin ( 926209 ) on Thursday March 01, 2012 @12:14PM (#39209649)

    Interesting. I worked phone support for a company, and their systems would occasionally do this. The delay was anywhere from a fraction of a second to a couple seconds, randomly for each call it happened to. It is really, really annoying, but I always assumed it made me stop talking because I was trying to be polite to the customer and when I hear a voice from their end, I'd stop and listen.

    It took me about a week to learn to just keep talking when I heard my own voice, and not someone else's.

  • by Tom Womack ( 8005 ) <> on Thursday March 01, 2012 @12:31PM (#39209969) Homepage

    This strikes me as an almost perfectly cliched Japanese technical solution to a social problem: you cannot accept the loss of face that would be involved in telling your minion Mr Akusake to shut up indicating that you do not have the degree of control over Mr Akusake that your relative positions would indicate, or the unspeakable loss of status that would be implied if you told your minion Mr Akusake to shut up and he didn't, but you can point the shutting-up machine at him and cause him to shut up.

    Loud people dominating conversations is undeniably an actual social problem, and this is an actual technical solution to it.

  • by Phreakiture ( 547094 ) on Thursday March 01, 2012 @12:49PM (#39210241) Homepage

    Having read how it works, I can tell you that being focused is enough to overcome this. It doesn't drown you out; it doesn't mute you. What it does is return your words to you about 200ms later so that you are dealing with a terribly strong reverse echo. This has a psychological effect on the speaker.

    By focusing, you can overcome it. I know this for a fact, because, as an A/V tech and DJ, I have spoken into a PA system that had a compressor on it, which compressor introduced about the same amount of delay. Even as I watched other people struggle with it when it was their turn to speak, I had no problems taking the mic and speaking, as long as I focused on what I was saying and ignored the feedback. (For the record, I used that compressor exactly once. It wasn't intended for PA use, but for broadcast, where the latency wouldn't have mattered.)

    If you can keep yourself focused on what it is you have to say, you can overcome this quite easily.

  • by Anonymous Coward on Thursday March 01, 2012 @12:59PM (#39210417)

    I remember reading an article a few years ago called "Conversational Ballgames" by an english-speaking woman who became fluent in Japanese while in residence there. She describes her difficulty fitting in to conversation patterns even after she was "fluent" until she learned that social expectations of the conversation differed across cultures. She compares western-style conversation to volleyball or tennis, a match where you bat back and forth the same ball with a partner -- whereas Japanese conversation reflects more a game of bowling. She explains the game:

    "A Japanese-style conversation, however, is not at all like tennis or volleyball, it’s like bowling. You wait for your turn, and you always know your place in line. It depends on such things as whether you are older or younger, a close friend or a relative stranger to the previous speaker, in a senior or junior position, and so on.

    The first thing is to wait for your turn, patiently and politely. When your moment comes, you step up to the starting line with your bowling ball, and carefully bowl it. Everyone else stands back, making sounds of polite encouragement. Everyone waits until your ball has reached the end of the lane, and watches to see if it knocks down all the pins, or only some of them, or none of them. Then there is a pause, while everyone registers your score.

    Then, after everyone is sure that you are done, the next person in line steps up to the same startling line, with a different ball. He doesn’t return your ball. There is no back and forth at all. And there is always a suitable pause between turns. There is no rush, no impatience."

    Here's a link to the essay:

    The reasoning given by the researchers for the need to silence someone (while still chilling) comes into context for me when I think of them trying to harmonize a game of bowling. I can see them pointing their silence gun at rowdy american-like bowlers butting into the lane when it isn't their turn, distracting the bowler on deck, and scooping the ball off the lane before it reaches the pins!

  • Re:Easy workaround (Score:4, Interesting)

    by rainmouse ( 1784278 ) on Thursday March 01, 2012 @02:04PM (#39211453)

    The speaker can simply block their ears. The gun works by sending the speaker's audio back to them with a delay.

    True but for silencing people who love the sound of their own voice this may be a godsend. Imagine staggering home at 4am to find the angry wife waiting up to give you hell and you pull this beast out and silence her.
    So far I have not found one on ebay yet..... I'll check again tomorrow.

  • Re:Easy workaround (Score:5, Interesting)

    by camperslo ( 704715 ) on Thursday March 01, 2012 @04:17PM (#39213545)

    The speaker can simply block their ears. The gun works by sending the speaker's audio back to them with a delay.

    Ahhh yes... people that listen to themselves delayed tends to slow down to nothing and stop. It messes up people on call-in talk radio, and some in radio too. People in broadcasting often listen to themselves as heard on the air in headphones and there many be a significant delay when net latency and satellite links are in the loop. They learn to cope, but it isn't easy. Even phase flippers can drive a person nuts. Voice is rich in even harmonics due to a lack of symmetry in the waveform which has a spikier character in one direction. In a.m. broadcasting some audio processing gear senses the stronger peaks and on the fly inverts the signal to make the higher level modulate the a.m. carrier up to 125% modulation. The signal can't go below nothing when the audio is reducing the r.f. envelope, but there's no limit other than an arbitrary regulation in the other direction. Anyway, an announcer hears a combination of his voice directly and what comes through the headphones, and the combination is awful when the phases don't agree. It jumping back and forth is torture for them. But if they listen to unprocessed audio, they don't have as good a feel for the mix so they usually endure.
    And people thought only the audience was tortured by radio...

Our business in life is not to succeed but to continue to fail in high spirits. -- Robert Louis Stevenson