Question

When the untrasound has more frequency than we can hear. But why do we hear a whirrring noise?

Answer 1

Explanation:

There are horrible sounds all around us only a small group of people can hear. They almost always come from machines — sometimes intentionally, and sometimes by accident. They're loud enough to be annoying and cause headaches in people sensitive to them, though it seems they aren't usually loud enough to cause permanent health issues. And scientists have no firm idea of how common these sounds are or how much damage, if any, they're doing to society.