Yamaha YST-SW515BL, YST-SW515 10" CUSTOM SERIES 270 Watts SLIM DESIGN Subwoofer YSTSW515BL, YSTSW515 Yamaha's YST-SW515 subwoofer combines 270W of power with advanced technology to provide top-class sound quality, making it an ideal match for your speakers. QD-Bass technology uses down-firing drivers with square, pyramid-shaped reflective plates to radiate the sound efficiently in four horizontal directions. The reflective plates (not used in competitors' down-firing subwoofers) negate any effects caused by the floor surface and reduce resonance between sound waves reflected from the floor and the unit. Unlike most other systems, QD-Bass reduces turbulence by radiating in four directions to avoid reflection from the legs of the cabinet. This means that the YST-SW515 generates extraordinary power and smooth frequency response from an extremely compact unit and allows greater freedom of placement, because the sound radiates with equal effectiveness in all directions. Yamaha's newly developed Advanced YSTII (Yamaha Active Servo Technology II) combines negative impedance and constant-current principles to drive the speaker cone with even tighter control than in previous models. Using Advanced Negative Impedance Converter (ANIC) circuits, this system dynamically optimizes effective speaker impedance to maintain excellent linearity. This means more stable and accurate low range response, not to mention higher sound pressure levels, for more natural and energetic bass reproduction. The YST-SW515 delivers high power outputs at deep bass levels, with excellent stability and low power consumption, even with its compact cabinet. This is made possible by a highly efficient power amplifier. The amplifier achieves superior conversion efficiency by supplying maximum power from the power transistors according to the output level. It delivers stable power output with high efficiency while minimizing power consumption and heat production. It does not require an output filter coil, resulting in extremely low noise and distortion. High-speed transient response is also excellent. The linear port provides smooth bass response during playback and minimizes extraneous noise. The BASS (Bass Action Selector System) function lets you switch between Movie and Music modes, providing the optimum frequency response in each case. The internal parts and circuit boards of the YST-SW515 do not contain lead, which is often used in other subwoofer brands, and is harmful to the environment. It also has a low-power standby mode, in which power consumption is only 0.5W. Height: 16.9 in Width: 13.8 in Depth: 15 in Minimum Frequency Response: 20 Hz Maximum Frequency Response: 160 Hz