What is a subwoofer, and do you need one? - SoundGuys
Woofer Vs Subwoofer Differences, Pros & Cons, And More
Amazon.com: Pyle 6.5 Inch Mid Bass Woofer Sound Speaker System - Pro Loud Range Audio 300 Watt Peak Power w/ 4 Ohm Impedance and 60-20KHz Frequency Response for Car Component Stereo PLG64,Yellow : Electronics
Jensen J12W 12-inch, 1200 Watts Polypropylene Subwoofer, Peak Power with Reinforced Stamped Steel Basket and 40oz Magnet - Walmart.com