Introduction to room acoustics
This chapter summarizes the basic concepts in room acoustics as a basis for sound insulation theory and building acoustic measurement methods. Wallace C. Sabin introduced the reverberation time concept in a pioneering paper published first time 1898 in Proceedings of the American Institute of Architects. There is no doubt that Sabine's formula is the most well-known formula in room acoustics, and it is widely used to calculate reverberation time. This means that using a stationary sound source, the sound field can be considered stationary after one-third of the reverberation time, and measurements can start. In a room with long reverberation time due to non-diffuse conditions and at least one sound-absorbing surface, introducing some sound scattering elements in the room can have a significant effect. It could be furniture or machines on the floor or some diffusers on the walls. This will make the sound field more diffuse, and the reverberation time will be reduced.