Amazon.com: 5 CORE 2500 Watt 18 Inch RAW DJ Speaker PA Subwoofer Replacement 8 Ohm Sub Woofer, Aluminium Frame, 4” Voice Coil FR 18 190 AL : Musical Instruments
Speaker plans, Subwoofer box design, Stereo idea
JBL PRX 418S 18 Inch Passive PA Subwoofer | American Musical Supply