Product Rating 
Dual 8" (20cm) Passive Radiator Design Powered Subwoofer Box (4O). Highly powerful yet surprisingly compact, this efficient unit uses two passive cones on the sides in addition to the active main cone to provide exceptionally high-quality, tight and accurate bass response. Features of the Alpine SWD-2030 include:
- Class-D Amplified Subwoofer
- Dimensions: 292(w) x 241/357(h) x 250/381(d) mm
- Diagnostic display
- Easy "one-plug" connector
- +/- 12V Power input
- Remote input
- High-power (speaker level) input
- RCA input (4V input compatible)
- Auto-On/Off selector (On function by remote signal or music signal)
- Selectable input (RCA or High-Power/Speaker)
- Phase Shift 0-180° adjust
- Low pass filter adjust 50-150Hz 12dB
- Level adjust (GAIN control)
- Soft limiter function
- System-tuned subsonic filtering
- Integrated ICEpower class-D amplifier with very low heat dissipation
- Two passive drivers
- 8" sealed subwoofer
- 350W Peak Power
- 150W RMS/250W max.
- Overload protection circuit