Subwoofer Yamaha NS-SW300 Pianoblack

Active subwoofer with Twisted Flare Port technology and a 250 W digital amplifier

The Yamaha NS-SW300 is an active subwoofer with a 25 cm (10") front-mounted cone bass driver, designed to extend the low end of home speaker systems and home cinema setups. The design is built around Twisted Flare Port technology — a gently twisted bass-reflex port with flared edges that disperses the air turbulence forming at the port mouth. The result is smoother airflow and suppression of noise that is not part of the input signal.

Power comes from a built-in high-efficiency PWM digital amplifier with a 250 W output that requires no output filter choke. This translates into exceptionally low noise and distortion, fast transient response, and lower power consumption as well as heat generation. The dual feedback circuit applies feedback twice, further reducing distortion. The driver uses a voice coil wound with square-section wire, which can be wound more densely and achieves higher magnetic flux density, and therefore greater driving force.

Cone control is handled by Advanced YST II (Yamaha Active Servo Technology II), combining the negative impedance and constant current principles. The ANIC (Advanced Negative Impedance Converter) circuits dynamically optimise the speaker's effective impedance and maintain linear response. In practice this means a more stable and accurate response across the 20–160 Hz band, clearer separation of individual bass instruments, and controlled, well-defined low-frequency reach in both film effects and live concert recordings.

The controls are grouped on a front panel angled at 45°, so power and volume remain accessible even when the unit sits on the floor; an LED above the power button indicates the operating status. A system connector allows power-on to be linked with the amplifier, while the Auto Standby function with selectable sensitivity (high, low, off) switches the unit into standby mode drawing just 0.3 W. A phase switch (normal/reverse) and B.A.S.S. (Bass Action Selector System) are also provided. Dimensions of 350 × 366 × 420 mm and a weight of 18 kg are complemented by a rounded front with side panels and a choice of colour finishes.

Key features

• Driver: 25 cm cone woofer with square-wire voice coil
• Amplifier: 250 W PWM digital amplifier with dual feedback
• Port: Twisted Flare Port for clean, controlled bass
• Control: Advanced YST II with ANIC circuitry
• Operation: Auto Standby, system connector, 0.3 W in standby