As children (possibly more recently), most of us tormented a classmate or sibling by “copying” them, e.g. repeating everything they said as quickly as you could say it. It’s one of those things that kids do to get under one another’s skin.
Most people find it difficult to finish a sentence or communicate an idea if someone parrots back to you everything you say. Some researchers in Japan have shown that, done correctly, it’s just about impossible, and there may be a practical application.
The device is called the SpeechJammer. It’s a directional microphone, targeting laser, computer, and directional speaker, all mounted on a platform that looks a little like a rifle stock. In use, the operator points the laser at the victim’s mouth to aim the microphone, then activates the circuit.
The directional microphone captures the speaker’s voice, runs it through a processor that delays it by about 0.2 seconds, and plays it back to the person speaking through a directional projector designed to confine the sound to their ears.
The effect is a little like Darth Vader using The Force to choke people who made him unhappy, albeit without the victim gasping and falling over dead. They simply become unable to speak. As soon as they say anything, they get the sound of their own voice fed back to them with that micro-delay, and it confounds the speech centers of the brain.
The fancy name for this method is Delayed Auditory Feedback. Whether we realize it or not, we are accustomed to hearing our own voices when we speak. If you start to speak and find that you’re hoarse or the pitch of your voice has changed (as happens when people play around with helium and it surrounds the vocal cords), you’re immediately aware of it.
If you temporarily lose your hearing, you’ll unconsciously try and compensate by shouting, even though others can hear you perfectly well at a regular volume. Ever notice that people tend to talk louder when they’re on cell phones? That’s because we’re accustomed to using regular phones that feed the sound of our voices back into the earpiece. Cell phones don’t do that, and we tend to shout because we’re acclimated to believe we won’t be heard if we don’t.
When the feedback is instantaneous or nearly so, there’s no interference with speech. Delay the feedback ever so slightly, and it’s like scrambling the firing order on your car’s spark plugs. The words just don’t come out.
A humorous video created by the SpeechJammer engineers shows some applications for the device that you’ve probably wished you could implement at one time or another: a person talking on their cell phone in an area designated for quiet, or a teacher who goes on talking long after the class period has expired. When I saw it, I thought of another, more practical application.
At many of the Occupy X demonstrations this past year, a popular device was the “human microphone.” One person would say something, and the crowd surrounding him would immediately parrot it back, achieving volume without the use of (often illegal) amplifying equipment. The chants were often intended to taunt and inflame the police into an overreaction that could then be recorded on video and exploited for propaganda purposes.
What if you had a SpeechJammer gun to aim at the human microphones, rendering them speechless? This is as close to a risk-free device as any I’ve seen. The projected sound is no louder than the speaker’s voice, and in the same tonal ranges. It’s not a “sonic weapon” that can injure hearing or even make anyone more than a few feet away aware that it’s being used at all.
This is a brand-new device, so there aren’t any commercial applications as yet. I’m hoping that the people at the National Institute of Advanced Industrial Science and Technology in Japan recognize the potential of this and bring it to the market.
SpeechJammer
