Amazon.com: Acoustic Audio WS1005 Passive Subwoofer Amp 200 Watt Amplifier for Home Theater : Electronics
The Difference Between a Passive and Powered Subwoofer
Amazon.com: MTX TN8MS Terminator 8 Inch Micro Compact Amplified Subwoofer Enclosure for Small Vehicles with Class A/B Amplifier, Variable Bass Boost, External Bass Control, and Smart Engage Auto Turn On Circuitry :