The term “critical distance” refers to the distance from a loudspeaker in an enclosed space at which the reverberation is equal in strength to the direct sound from the speaker. Beyond this distance, the reverberant energy tends to mask the direct sound. In truth, because reflected sound loses energy to boundary absorption (and also travels a longer path to the listener, thus incurring greater air absorption losses), the reverberant energy from a discrete pulse sound stimulus can never equal the direct sound on an instantaneous basis. In highly reflective environments, however, the steady-state reverberation strength can easily exceed that of the direct sound at many locations in the space. This degrades the signal-to-noise ratio and destroys intelligibility. Return to

The distance from a sound source at which the reverberant sound is equal to the direct sound. A very reverberant room has a short critical distance while an acoustically dead room can have a much longer critical distance. Room treatment types and speaker choice affect critical distance.

The point from the sound source where the direct sound and the reverberant sound are equal in volume

The distance from a sound source in a room at which the direct sound and the reverberant sound are equal in level.

The distance from a sound source at which sound pressure levels emitted by the source equal those being reflected off of other surfaces.

In acoustics, the distance from a sound source in a room at which the direct sound level is equal to the reverberant sound level.

a component of the flight distance, distance at which the animal feels forced to defend itself

In audio physics, the distance at which the sound pressure level of the direct and the reverberant field are equal. In other words, the point in space where the echo from a sound source is at the same volume (amplitude) as the source. This distance is dependent on the geometry in which the sound waves propagate, as well as the dimensions and shape of the sound source.