Sony XS-L100P5H 10" 4-ohm subwoofer at Crutchfield
JBL PRX915XLF Professional Powered 15" Subwoofer – Easy Music Center
CRITICAL MASS UL12 MSRP $14K BEST SPEAKER SUBWOOFER EVER MADE SQ AUDIOPHILE HIFI | eBay
PRORECK Club 3500 15-inch 3000W P.M.P.O DJ Speakers with Subwoofer, Powered PA Speaker System with Built in Amplifier Stereo Combo Set 8 Array Speakers and 15 inch Active Subwoofer with Bluetooth, USB - Walmart.com