Thursday, October 31, 1985 3:30 p.m.
Department of Electrical Engineering
The University of Texas at Austin
In recent years, the thrust in acoustic horn loudspeaker design has shifted from impedance matching and power transfer to radiation pattern control. Although the two criteria are not completely incompatible with one another, horn designs which satisfy both are complex and have yet to be perfected. The major difficulty in designing such horns is the lack of a method by which composite acoustic waveguides may be analyzed. Fortunately, the two-port theory underlying microwave waveguide system design is fairly well developed. This theory allows approximate analysis of waveguide discontinuities and tapers in composite microwave waveguide systems. In recent years, this theory has been extended to an N-port analysis using coupled transmission lines which allows accurate analysis of systems in which mode conversion occurs and multiple propagating modes exist. We are in the process of borrowing this theory almost intact from an obscure book published in West Germany so that hopefully everyone will think we thought of it ourselves.
Although, the N-port theory has yet to be implemented, the two-port theory has yielded some interesting predictions which are in disagreement with those published in several well-known books. We plan to present experimental data which will hopefully justify our predictions.