Evaluation of efficiency and voltage sensitivity in horn drivers

摘要

There is a belief in horn driver design that if the resistive component of the diaphragm's input acoustical load impedance is equal to the DC component of the voice coil's electrical impedance, a maximum efficiency of 50% can be reached. This work shows that in reality, the compression driver's real efficiency differs from the classical theory prediction. The discrepancy is explained by the fact that the driver's output impedance and the acoustical loading impedance are different functions, not mere resistances. Additionally, the input electrical power and the output acoustical power are essentially integral functions of frequency and can be expressed by single numbers rather than frequency-dependent functions. Examples illustrating the dependence of efficiency and sensitivity on various parameters are given.