Abstract: Some concepts based on the data given in the book "Concert Halls and Opera Houses" by Leo Beranek are presented through some simple mathematical process. The intensity factor G is related to the number of seats N by linear regression. The EDT equals to reverberation time for concert halls with N ≥ 2000 and the calculation of EDT is given for N ＞ 2000. The number of seats is the start point of determination of volume for both concert halls and opera houses.