SMP200 Class D Digital Subwoofer Amplifier may be compact, but with 200W of power, this little amp packs a powerful punch. Designed to power passive subwoofers used in home theaters or whole house audio systems, the SMP200 measures less than nine inches wide and 10 inches deep but supplies an in-wall or stand-alone subwoofer with the power it needs so you can experience that gut wrenching, heart pounding low frequency impact (bass) on movie and music soundtracks. The advanced crossover circuit can be set at different frequency ranges (35Hz to 160Hz) and can be adjusted with the front-panel control knob. Other features include front-panel adjustable phase and volume controls to dial in just the right amount of low frequency effects (LFE).