Some aspects of crossover design to correct for the time offset due to acoustic center displacement in coaxial transducers are examined. The effect of this time delay on the magnitude response of first-, second-, and third-order crossover networks is isolated from the entire crossover-transducer system. This is accomplished by examining the steady-state vector sum of outputs of a transfer function model of the low-pass filter, the high-pass filter, and the time-delay portions of the entire system. Second, Bessel low-pass and all-pass networks are analyzed as approximations to the spatially related time delay. The magnitude and group-delay characteristics of second- and fourth-order networks of these types are examined. Finally, the magnitude of response of crossover networks employing time-delay approximation networks is considered. The model used to evaluate the effect of time offset on crossover networks is modified to include the compensation effects of the Bessel low-pass and all-pass networks.
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