Excellent Bass for Movies and Music This subwoofer incorporates a number of Yamaha advanced, high-performance bass technologies, such as Twisted Flare Port, Advanced YST II (Yamaha Active Servo Technology II) with discrete amp circuitry and a high-quality 10" woofer unit. The resulting bass response is powerfully rich and impactful. New Twisted Flare Port contributes to clear and tight bass Advanced YST II (Yamaha Active Servo Technology II) 10" Cone woofer Stylish addition to any room Clear and Tight Bass The new Twisted Flare Port takes advantage of extensive subwoofer development experience. The gently twisting flared shape creates a smooth flow of air around the edge of the port versus the turbulent air flow around a conventional port. This reduces extraneous noise not present in the original input signal and provides clear, accurate low frequency reproduction. From special effect sounds in movies to the atmosphere of a live venue, you hear bass that is clear, tight and realistic. Deep Lows Developed by Yamaha, the Advanced YST II (Yamaha Active Servo Technology II) combines negative-impedance and constant-current principles to drive the speaker cone with even tighter control than the previous version. Using Advanced Negative Impedance Converter (ANIC) circuits, this system dynamically optimizes effective speaker impedance to maintain excellent linearity. This means more stable and accurate lo