The prediction of nonlinear resistance and distortion for a miniature loudspeaker with vented cavities

The nonlinear resistance and its influence on the total harmonic distortion of a miniature loudspeaker with vented cavities are investigated. A method for the prediction of nonlinear resistance is described. In the model, the nonlinear resistance caused by the magnetic gap and the orifices in the back cover of the miniature loudspeaker is taken into account. The nonlinear acoustic resistance is estimated through the electric analogy method, and then it is transformed into the equivalent nonlinear resistance of the vibrating diaphragm. The estimated nonlinear resistance is verified through the Klippel Analyzer measurement. The influence of the nonlinear resistance, mechanical stiffness and force factor on the total harmonic distortion is calculated and compared with the measurements.