The Yamaha YST-SW215 powered subwoofer features an 8-inch cone driver and a 120-watt amplifier, the latter ensuring enough power to deliver shattering, movie-theatre-like bass effects, and the former translating the power into clear bass sound. The speaker also includes Yamaha’s Advanced Active Servo Technology, a complementary amplifier/speaker system that utilizes negative impedance feedback in the amp and a Helmholtz resonator in the speaker to provide strong and accurate bass tones. Other features include a BASS (Bass Action Selector Switch), which tailors the sub’s output for video or music at the touch of a switch, and QD-Bass Technology, which uses a down-firing driver to radiate the sound in all directions for greater impact. In addition, the user-adjustable high-cut filter sets the highest frequency the subwoofer will deliver (anywhere from 50 to 150 Hz). If the filter is set at 75 Hz, only frequencies below or equal to 75 Hz will be delivered. This allows the user to match the sub with other speakers in the system and the room’s acoustics. The subwoofer has an overall frequency range of 30 to 200 Hz.
The YST-SW215 also features magnetic shielding, which lets you place the speaker on a TV or video monitor without degrading the picture, and individual volume control so you can match the sub’s output to the system’s volume. To further increase efficiency, the sub’s auto signal on/off detects when an audio signal is no longer present and shuts off after several minutes. Yamaha also made it easier to phase the subwoofer into your system with its Phase Normal/Reverse switch.
The sub features dual inputs that accept either line-level or speaker level input signals, and the three-way speaker terminals accept banana plugs and a variety of other speaker connectors, as well as speaker wire. The sub is constructed of thick MDF to increase rigidity and reduce vibration and resonance, and it also fits with a variety of room dcor due to its handsome black ash finish.