- Critical distance
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Critical distance is, in audio physics, the distance at which the sound pressure level of the direct and the reverberant sound fields are equal when dealing with a directional source. In other words, the point in space where the amplitude of a reflected echo is the same as that of the source. This 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.
A reverberant room generates a short critical distance and an acoustically dead (anechoic) room generates a longer critical distance.
The calculation of the critical distance:
or:
γ is the degree of bundling of the source, V the room volume in cubic meters, RT60 the reverberation time of room in seconds, and A the equivalent absorption surface.
Avoid the words Reverb Radius, Reverberation Radius (omnidirectional source), Hall Radius for Critical Distance.
This distance, called critical distance dc, can be specified as a function of room volume and reverberation time using Sabine's approximation:
Critical distance dc in m
Room volume V in m3
Reverberation time RT60 in sListen to this article (info/dl)
This audio file was created from a revision of Critical distance dated 2006-12-17, and does not reflect subsequent edits to the article. (Audio help)More spoken articlesCategories:- Acoustics
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