The standard method for specifying reverberation time, RT60 is the amount of time it takes for the reverberant energy in an enclosed space to drop by 60 dB from its initial, steady-state value after the original sound has ceased. Large rooms with hard, highly reflective surfaces (like cathedrals) have long reverberation times, while smaller rooms with absorptive surfaces have short reverberation times. Here is a diagram that gives preferred RT60 values for various applications. Return to