direct-to-reverberant ratio

10.24 direct-to-reverberant ratio. At a given location, the ratio of the sound pressure level of a direct sound from a directional source to the reverberant sound pressure level simultaneously incident to the same location. Unit, decibels (dB).

Annotation              The critical distance is achieved at a direct-to-reverberant ratio of 0 dB (see 10.23).