The Use of Volume Velocity Source in Transfer Measurements

In the automotive industry there is a growing need for measurement of acoustical transfer functions in connection with transfer path analysis, the main outcome being acoustical source contribution analysis. These transfer functions are from monopole Volume Velocity at a source location to the resulting sound pressure at a receiver (listener) position. In most cases it is an advantage to make use of reciprocity, which allows the monopole source position and the pressure response position to be interchanged. The source to be used for these measurements must be powerful and omni-directional, and the frequency range of interest is typically 50-6300 Hz. So the Brüel & Kjær OmniSource™ is in many ways perfectly suited for the application. This paper will discuss the design criteria for a Volume Velocity Source as well as the verification of the performance. Also the use of Volume Velocity Source in Transfer Path Analysis often called Source Path Contribution is described. Practical examples using the Volume Velocity Source will be shown.