Sound&Vision: Advertiser: 4 Reasons to go with Dual (or more) Subwoofers
Dual SD12 12" Single 4 ohm SD Series Car Subwoofer
Amazon.com: Dual Electronics SBX212i 12-inch illumiNITE High Performance Studio Enclosed Subwoofers with 1,200 Watts of Peak Power & 41-Ounce Magnets : Electronics
S212 | Dual 12" Enclosed Subwoofer – exileaudio
How to Make Dual L-Ported Subwoofer Box - DIY - YouTube
Dual Electronics - 10" Subwoofer in a Vented Enclosure - SBX101
Amazon.com: Dual Electronics BP1204 High Performance 12 inch Car Audio Subwoofers in a Tuned Bandpass Enclosure with Blue illumiNITE LED Illumination and Plexiglass Viewing Windows and 1,100 Watts of Peak Power : Electronics
Pyle 10" Dual Series Vented Subwoofer Enclosure-High Powered Sub Woofer Speaker | eBay