The Acoustical Impedance of an Infinite Hyperbolic Horn
John Edwin Freehafer · The Journal of the Acoustical Society of America · 1940
In discussing the acoustical properties of horns, it is in general a mathematical necessity to assume plane waves. In the case of a horn in the form of an hyperboloid of one sheet, however, it is possible to avoid this assumption and to obtain an exact solution to the problem. The analysis, carried through with the aid of the differential analyzer, leads to curves representing the acoustical resistance and reactance as functions of the ratio of the radius of the throat to the wave-length. Comparison with the conical horn shows that the hyperbolic is superior.