Short reverberation time
The reverberation time (T) is defined as the time it takes for the sound level to decrease with 60 dB.
In most premises comfortable room acoustics depend directly on a short reverberation time. Rooms intended for conversation, or where a high degree of privacy is required, are most dependent on short reverberation times.
The easiest and most cost effective way to achieve a pleasant acoustic environment is to install a wall-to-wall acoustic ceiling system that provides high sound absorption.
A sound in a room is still audible a short time after the source has ceased. This is due to the fact that the sound is partly reflected from the room's perimeter surfaces, thus giving a kind of echo. Room volume, room shape, the amount of sound absorbing material and sound field diffuseness will also determine the reverberation time. Under ideal conditions the reverberation time can be estimated by use of the Sabine formula. In many cases, however, such calculations give values that are too low, which is due to lack of diffuseness. A diffuse sound-field
means that the sound waves are evenly distributed in a room. There are different types of more qualified methods for calculation of reverberation time, but they should only be handled by acoustic experts.
The total amount of sound absorption in a room and hence the reverberation time, is critically important for speech intelligibility
and sound levels, among other things.