Technique for subwoofer distance measurement

Abstract

The present invention automatically corrects for subwoofer or other speaker crossover settings or other parameters by providing an adjustable factor passed upon not only pulse location, but on pulse width. In FIG., as the low-pass frequency of the subwoofer is decreased, either by the crossover setting or the physical design of the subwoofer, the impulse response is shifted to the right and the width of the impulse increases. By relating the adjustment factor to the width of the impulse, the accuracy of the computed distance is greatly increased. The relation may be found doing a simple polynomial curve fitting to empirical data from several subwoofers at various crossover settings and distances, storing that data, and then measuring pulse location and width of the actual subwoofer during the setup routine, and adjusting the distance (delay) calculations accordingly.