Maybe, as often happened, they underrated the reach of human hearing.

Perhaps the sounds were all too high-pitched for human hearing?

"They are making sounds far above the range of human hearing," Data whispered.

This sound is above the range of human hearing.

But if the waves are too small, they lie outside the range of human hearing.

In only a few moments, they were out of human hearing.

With her more than human hearing, she heard it all.

For one thing, the sounds are outside the range of human hearing.

The sounds were just below the limit of human hearing.

Explore how human hearing and some cool technology allow two speakers to sound like five.