Wednesday, April 16, 1986 4:00 p.m.
Christopher L. Morfey
The Institute of Sound and Vibration
This tutorial lecture will look at the way modes are used to describe the linear acoustic response of ducts and rooms to sources of sound. Beginning with the unforced situation, first the propagation of duct modes (with respect to the axial coordinate) is discussed and illustrated with examples; second the same procedure is followed for room modes, with t as the propagation coordinate.
Sources of sound are then introduced via jump conditions in the propagation direction. In this way the apparently disparate problems of room and duct excitation are given a unified conceptual basis. Some awkward points in the classical (Morse and Bolt) treatment of room response are thereby avoided.