Time Alignment of Subwoofers in Large PA Systems
In common PA systems the frequency range is divided into different ranges that are reproduced using different cabinets (subwoofers for the bass range and top cabinets for the mid-high range). This means different locations and positions of the sound sources and therefore notches and peaks in the crossover range. Time alignment is needed to adjust the arrival time of frequencies in the crossover area. But it's not only a matter of distance, since the crossover is modifying the phase, too. In this brief, a downscaled model is used to show how to measure the phase difference of a two-source PA system and correct it using FFT measuring software. Two situations are treated: two sources with overlapped frequency response and two sources sharing crossover frequency.
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