
A spring-suspended, moving-coil transducer to be tuned is mounted on a dynamic test fixture and excited by an oscillatory driving force calculated to drive the transducer at a desired resonant frequency. A laser beam, sensitive to a difference between the actual resonant frequency of the transducer and the desired resonant frequency, is focused on the spring. The energy of the laser beam alters the elastic constant of the spring by trimming or etching material therefrom until the difference betw...











