The calculation model in Acousticfacts.com
uses Sabine’s relationship between the total amount of sound absorption in a room and the room’s reverberation time. In essence, the relationship states that the reverberation time is lowered if you introduce more absorption.
Calculations are made in
the octave bands 125, 250, 500, 1000, 2000 and 4000 Hz. This means that the total sound absorption from the room itself (including an absorbing ceiling) and from all furniture and wall absorbers is summed in each octave band. Sabine’s relationship is then used to calculate the corresponding reverberation time in each octave band. These values can be seen for your individual rooms by pressing the graph button.