15 VS 12 Inch Subwoofer: What's the Performance Difference?
Amazon.com: Sound Town 15” 500W Cast Aluminum Frame Woofer (Low Frequency Driver), Replacement Woofer for PA/DJ Speakers or Subwoofer Cabinets (STLF-15120A) : Musical Instruments
Amazon.com: 5 CORE 18" Raw 850W Peak Sub Woofer Cast Steel Basket Driver for Pro Audio PA DJ Cabinets Subwoofer with High Handling Power 500W RMS Extremely Clear and Loud Replacement Speaker