Critical distance

Critical distance is, in audio physics, the distance at which the sound pressure level of the direct sound D and the reverberant sound R are equal when dealing with a directional source. In other words, the point in space where the combined amplitude of all the reflected echoes are the same as the amplitude of the sound coming directly from the source (D = R). This distance, called the critical distance , is dependent on the geometry and absorption of the space in which the sound waves propagate, as well as the dimensions and shape of the sound source.