If you are a frequent Zoom caller, you’ll know that the single most annoying and disruptive occurrence is the dreaded echo. Hearing your own voice played back to you with a slight delay is so viscerally irritating, it renders it impossible to talk coherently, and you end up shouting "can everyone mute their microphones please!" before you lose your entire train of thought.
The US Navy is clearly aware of this phenomenon and is apparently seeking to use it as a non-lethal weapon that makes it almost impossible to speak. A new device called the handheld acoustic hailing and disruption (AHAD) system uses a long-range microphone to record your voice before powerful speakers replay that speech on a slight delay back to the individual. The constant loop of speech makes it extremely difficult to continue conversations or relay messages, a vital tool in the military.
Despite filing for the patent in 2019, it has only recently been granted to the Navy just this month.
To make it even more disruptive, the inventors suggest using a directional speaker, which can transmit sound precisely to a small area, to target individuals, so everyone can have a conversation with themselves. People in the vicinity would have no idea the other person is being targeted. Imagine trying to have a coherent conversation in an online meeting with everyone having terrible Internet and their microphones off mute – truly a nightmare.
As to why the Navy has put such intensive research and almost three years into this technology, that remains a mystery.
The technology is based on the principle of delayed auditory feedback (DAF). DAF has been used previously in aiding people who stutter, as some individuals have altered auditory systems that cause the stutter and seem to be helped by introducing a loop of their own voice. However, in those who do not stutter, the loop can be extremely disruptive to the majority of people. There does appear to be a group of people that can resist the effects and continue talking, particularly those that speak fast or are trained in public speaking, so while the weapon may entirely halt some people's speech, others may be relatively unaffected.
According to an interview with cognitive neuroscientist Sophie Scott with New Scientist, the delayed feedback inhibits the ability to control our own voice. Some may begin stammering, some may stop talking altogether, while others will begin to distort their speech. On a ship in the middle of a battle scenario or as a key communicator or even translator, this could be extremely problematic.