Tristero's story

After he lost much of his hearing last year at age 57, the composer Richard Einhorn despaired of ever really enjoying a concert or musical again. Even using special headsets supplied by the Metropolitan Opera and Broadway theaters, he found himself frustrated by the sound quality, static and interference.

Then, in June, he went to the Kennedy Center in Washington, where his “Voices of Light” oratorio had once been performed with the National Symphony Orchestra, for a performance of the musical “Wicked.”

There were no special headphones. This time, the words and music were transmitted to a wireless receiver in Mr. Einhorn’s hearing aid using a technology that is just starting to make its way into public places in America: a hearing loop.

“There I was at ‘Wicked’ weeping uncontrollably — and I don’t even like musicals,” he said. “For the first time since I lost most of my hearing, live music was perfectly clear, perfectly clean and incredibly rich.”

His reaction is a common one. The technology, which has been widely adopted in Northern Europe, has the potential to transform the lives of tens of millions of Americans, according to national advocacy groups. As loops are installed in stores, banks, museums, subway stations and other public spaces, people who have felt excluded are suddenly back in the conversation.

A hearing loop, typically installed on the floor around the periphery of a room, is a thin strand of copper wire radiating electromagnetic signals that can be picked up by a tiny receiver already built into most hearing aids and cochlear implants. When the receiver is turned on, the hearing aid receives only the sounds coming directly from a microphone, not the background cacophony.