Polk Audio db1212 Ported enclosure with one 12" db Series subwoofer at Crutchfield
Polk Audio 12-Inch 720W Subwoofer with Vented Box Enclosure | DXI122 - YouTube
Polk Audio GNX124 Car Subwoofer User Manual
Polk Audio dX10 10" 4-ohm Component Subwoofer at Crutchfield
Polk Audio DB842DVC DB+ Series 8 Inch Dual Voice Coil Shallow Subwoofer with Marine Certification
Polk Audio PSW505 12" Powered Subwoofer - Deep Bass Impact & Distortion-Free Sound, Up to 460 Watts, Easy Integration with Home Theater Systems, BLACK : Electronics
Polk Audio DB1222 Car Subwoofers Look/Review - YouTube