Acoustics is something we all have to deal with in audio. In the studio, you might use it to your advantage to get that great drum sound or guitar sound. In live sound, it might be your worst nightmare. Either way we all should know and learn something about acoustics.
In 1922 a pioneer in the study of room acoustics, Wallace Sabine came up with the formula which is used here by this calculator.
RT60 is an acoustical measurement used to calculate reverb time decay. What RT60 really is in simple terms is the measurement of time it takes a signal to fall -60db.
RT60 = k*(V/Sa)
k is a constant that equals 0.161 when the units of measurement are expressed in meters and 0.049 when units are expressed in feet. Sa is the total surface absorption of a room expressed in sabins. It is a sum of all the surface areas in the room multiplied by their respective absorption coefficients. The absorption coefficients express the absorption factor of materials at given frequencies. The figures used in this calculator come from the table of absorption coefficients for various materials which can be found in any book that talks about room acoustics.