Abstract
The sum of the structural kinetic energy and acoustic power is a reasonable error criterion to control both vibration and sound. The orthogonal contributor to this error criterion, vibroacoustic mode, has been formulated by the authors. Modal filter for the vibroacoustic mode is frequency dependent spatial filter, and thus its implementation is not very easy. The frequency dependence of the modal filter should be omitted to facilitate its implementation, if the omission is permissible. Weighting filter, which gives added weight to each vibroacoustic mode on the basis of its contribution to the error criterion, is frequency dependent filter. The frequency dependence of the weighting filter holds the key of order reduction on the basis of the vibroacoustic mode. In this paper, the frequency characteristics of the modal filter and weighting filter are investigated through the theory and numerical simulations.
