ABSTRACT
The equations derived in the previous chapters have been presented from the input-output or transfer function approach. The value of pressure or spectrum in the ˜eld was presented in terms of values on a surface. In a theoretical sense, neither the values of pressure on a surface nor ˜eld values are known; these relations are merely integral equations that are the counterpart of the differential equations of acoustics. However, if one takes a different view of these relations, it is evident that if the values over a surface are known or can be measured, then the ˜eld values can be computed. Conversely, if the ˜eld values are known, then the values on the surface can be approximated. With this approach in mind, several applications of the fundamental equations shall be considered.
