A program was developed which calculated sound pressure levels at an array of points in a room. Necessary inputs are the room dimensions, sound power or sound pressure levels for the sources, absorption coefficients for the room surfaces, the temperature, relative humidity, and if sound pressure levels are given for the source a description of the room in which this measurement was taken. This program allowed a maximum of twenty-five sources. Calculations were made at eleven octave bands from 16 Hz. to 16,000 Hz. and converted to dBA levels. The basis for these calculations was a modified room acoustics equations. The modifications were: a factor modifying the reverberant 1 term, continually monitoring directivity with respect to changing distance of receiver points from the source, the inclusion of air absorption on the direct term and corrections for receiver points in close proximity to room surfaces, The modification to the reverberant g term was to simulate the departure from the assumption of constant energy density in irregularly proportioned rooms. The modification when receiver points were near a room surface was simply the addition of corrections to calculated sound pressure levels. / Master of Science