Frequency

Between 2 and 4% of the world's population report hearing a mysterious buzzing or vibration. It's called The Hum, and for decades, scientists, engineers, and ordinary people have been trying to figure out what it is.

Imagine talking to someone across a crowd of thousands without using a phone, or sitting way up the back at a concert, but hearing everything perfectly. This is the promise of acoustic lenses, and researchers at the universities of Sussex and Bristol in the UK think they’ve something to shout about.