10" cone driver 250W Amplifier 20 to 160 Hz frequency range Advanced Active Servo Technology --is an amplifier/speaker system utilizing negative impedance feedback in the amp and a Helmholtz resonator in the speaker to provide strong and accurate bass.BASS Selector Yamaha s QD-Bass Technology Magnetic Shielding Continuously variable high-cut filter sets the highest frequency the subwoofer will deliver. It can be set anywhere from 40 to 140 Hz. Volume Control Signal Sensing ON/OFF: When the subwoofer detects an audio signal; it turns its power on. Phase Normal/Reverse Switch Dual Inputs-- allow the versatile subwoofer to accept either line level or speaker level input signals. Three-way speaker terminals Black Ash finish The YST-SW315 s cabinet is constructed of thick MDF to increase rigidity and reduce vibration and resonance.