An Earplug That Lets the Good Sounds In

Researchers at the Sintef Lab at the Norwegian Institute of Technology have invented a tiny, smart earplug that could make noisy environments a little easier on everyone's ears. Consisting of a form-fitted earpiece, digital signal processor, speaker, and two microphones, the Personal Active Radio/Audio Terminal (PARAT), filters out human voices from the background din and makes conversation possible in previously hostile environments.

In quiet conditions, the earplug "opens up" so the wearer can hear everything normally. However, once the device's external microphone picks up significant outside noise, its main processor begins to filter incoming signals. Programmed to recognize sounds that occur in the unique spectrum of the human voice, the device relays these--but not other noise--to a miniature speaker in the eardrum. There, a second microphone monitors the sound level, making sure that voices don't get too loud.

With wireless phones popping up everywhere, the technology has enormous potential to silence the cell-phone shouting matches common at many noisy airports and bars. But the smart earplugs also hold out promise to workers who must communicate amid cacophony. "This can replace the big ear mufflers used in factories, airports, and on oil rigs," says senior researcher Jarle Svean. The plugs may start finding their way into commercial applications, and into users' ears, in as little as a year.

By Adam Aston

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