Formulas pertaining to the calculation of noise in a room produced by a steady source, the measurement of sound power in a reverberant room, and the calculation of reverberation time are reviewed for their appropriateness to engineering use. It is recalled that the simple Sabine reverberation equation can be used without loss of generality provided one associates with a given sound absorbing material a coefficient which is the negative natural logarithm of the energy reflection coefficient; the name Sabine coefficient is tentatively suggested for this quantity. It is noted further that the coefficient usually obtained from tests in a reverberation room is the Sabine coefficient and not truly the sound energy absorption coefficient. A relation is given, between average sound pressure in a room and the power delivered by a source, that does not require averaging absorption coefficients and which is only slightly dependent upon the mean free path. The “Sabine absorption”Sāis more nearly correct (and easier to compute) than the room constant,Sᾱ/(1 −ᾱ) both for the sound‐pressure‐power relationship and reverberation time calculation, whereSis the wall area,āthe average Sabine coefficient, and ᾱ is the average energy absorption coefficient. For sound power level calculations appropriate graphs are provided, showing dependence of intrinsic acoustic impedance and bulk modulus on temperature and barometric pressure or salinity, for air and water, respectively.