The mechanical impedance of an electromagnetic speaker is affected by current flowing in the electrical elements, just as the electrical impedance is influenced by the motion of the mechanical system. This paper gives the relation between mechanical impedance and electrical load impedance, making use of the three complex speaker constants evaluated by the motional impedance method presented earlier by R. D. Fay. Measurements are given showing that the mechanical impedance of a WE5S5 horn driver can be varied over a fairly wide range.
Figures & Tables
Seismic Wave Propagation: Collected Works of J. E. White
This first chapter sets the stage for the later technical development of Dr. Whit’s career in applied seismics. Experiments, f’wst at the Acoustics Laboratory of the Massachusetts Institute of Technology and later at Mobil Oil and Marathon Oil, provided insight into the general problems of impedance measurements, transduction, filtering, and attenuation. These papers also serve as a bridge to show geophysicists how theft own experiments in seismology naturally interface with (indeed, arose out of) the larger world of sound measurements in air and water. These experiments demonstrate the power of geometrically constrained experiments to allow verification of approximate (and in some cases, exact) theories of sound.