Fostex PM-SUB-MINI-2 Powered Subwoofer 5 Inch with Auto Standby Switch
The Best High-Performance Subwoofer | Reviews by Wirecutter
Subwoofer auto-standby problem | AVS Forum
Amazon.com: Powered Subwoofer, Konex 12" Woofer 300W Powered Active Subwoofer, High Connectivity, Low Impedance Inputs & Line Input, Standby Mode, for Studio & Home Theater, Black : Electronics