Sound sources

Abstract

For the discussion of plane waves, we concentrated on the sound field at arbitrary observation points. We did not consider sound sources. Characterization of sound sources, however, is one of the most important tasks in simulation and auralization. A first approach to a physical description of a source can be found in solving the wave equation in polar coordinates. At the origin of the coordinate system, at r = 0, we assume a small, point-such as source (dimensions « λ), called a monopole, which emits a certain volume per second. The source is characterized by its capacity to set particles in the medium into motion. The corresponding strength is denoted as “volume flow” or “volume velocity.”