The sound of silence

How it works

An anechoic chamber is a room built to absorb sound. Its walls, floor, and ceiling are covered in deep foam wedges. They soak up about 99.99% of the sound that hits them¹. There are no echoes. Outside noise is blocked by thick walls and springs under the floor.

Inside, your ears have nothing to hear from the room. So they hear you. Within a few minutes most people notice their heartbeat. Then the whoosh of blood in the neck and head. Then the hiss of breath and the creak of joints. Some people hear their stomach. The brain also turns up its own gain when input is low, so faint signals feel loud.

Many people also hear a thin, high ringing. Part of this is the inner ear itself. The outer hair cells of the cochlea move and make faint sounds called otoacoustic emissions². In 1953 Heller and Bergman put people with normal hearing in a quiet room³. Most of them reported ringing, buzzing, or humming³.

The quietest room ever measured is at Microsoft in Redmond, Washington. It reached -20.6 dBA in 2015, which is below the threshold of human hearing¹. Before that the record belonged to Orfield Laboratories in Minneapolis, at -9.4 dBA¹.

History and culture

A story says that nobody can stay in the Orfield chamber for more than 45 minutes¹. This is a myth. People find the room strange, and some feel dizzy because they lose the sound cues they use for balance. But people have sat in anechoic chambers for hours. The room does not harm you. It only shows you how much noise your own body makes.