Analysis of Crossover Design in Custom-Built Stereo Speakers
The purpose of this project was to investigate the effects of the crossover filter circuitry, located inside of the speaker enclosure, on the response of the speaker. Specifically, this project assessed the effect of a higher order filter on the flatness of the speaker’s overall response. The speaker was designed around two HiVi brand drivers, a woofer and a tweeter. The enclosure was designed to avoid unwanted resonance and tuned to about 53 Hz, based on the woofer manufacturer’s specifications. The crossover circuitry was designed with selectable first and second order configurations, along with switched circuits for tweeter attenuation and woofer impedance correction. For testing, the speaker was placed in an anechoic chamber with a function generator and a sound level meter, and output levels were recorded across the audible spectrum. The speaker also underwent a listening test, and the crossover filter was tested with an oscilloscope. It was shown that the second order filter provided a slightly flatter frequency response than the first order filter. However, the flattest response was achieved by activating the second order filter with tweeter attenuation and woofer impedance correction. The oscilloscope test supported this result, as did the listening test.