1. A method for evaluating the performance of a transducer horn assembly used in a debubbling operation, the method comprising the steps of: (a) connecting a test circuit between the transducer horn assembly and a signal analyzer; (b) supplying power to the transducer horn assembly; (c) operating the transducer horn assembly on-line in a debubbling operation; (d) sampling the electrical signals applied to the transducer horn assembly during said operating step; (e) transmitting the sampled electrical signals to the signal analyzer; (f) maintaining the amplitude and phase relationship of the sampled electrical signals; (g) determining the operating frequency of the transducer horn assembly from the sampled electrical signals; and (h) determining if the operating frequency of the transducer horn assembly is between a series resonance frequency and a parallel resonance frequency of the transducer horn assembly.