Do subwoofers need amplifiers?

Note: It is not compulsory a subwoofers need amp
If you want more “boom” from your music or want to feel Like gunfire and blasts in your body while gaming or watching action movies, a sub-woofer will get you there,

  1. The very low frequency noises are the same in both the left and right channels, and the signals from the higher frequency audio can be filtered out. So either a signal is sent to the subwoofer module from an amplifier where the left and right channels have been added and the higher frequencies have been subtracted, or the amplifier’s two high-power outputs are sampled and sent to the subwoofer as well as speakers.
  2. The l and r channels need power amps in any event.
    Again Note : that the subwoofer has its own very powerful single channel amplifier.