Anechoic room
This anechoic room is covered with special materials so that the room itself absorbs all reverberations.
We usually grasp the extent of the space around our body by reflected sounds. However, in this special space where there is no resonance or reflected sounds or any permeation of sound from outside, you cannot define your position, just like being suspended in space without any form of orientation. That is why you might experience feelings of pressure or uneasiness in this room. This spatial characteristic of an anechoic room is also used to experiment in creating artificial relationships between the visitor and the environment via sound.

An American composer John Cage (1912-1992) once tried to experience complete silence in an anechoic room. Although he was supposed to be blocked from any sound, he heard two kinds of noises in his body, "the sound of his blood pulsing" and "the sound of his nerves". Through this experience, Cage recognized that there is no such thing as silence, which led to the creation of his silent piece titled 4'33'' (1952).