The demand for high-level low-frequency sound in a cinema and home theater audio systems, and the desire for compact subwoofers, is the motivation behind the work. Tapered ports were believed to perform better than simple ones, and this study sets out to measure and analyze such ports and assess their performance. A model of an acoustic port of varying cross-section is presented. Acoustic ports of various shapes are studied to show their behavior at a range of levels. It is found that flared ends do help, but at high levels, some losses and distortion remain. A gently-tapered port shows better behavior.
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