How Speakers and Subwoofers Work
Diagram of a speaker.
The electrical current comes into the speaker motor assembly through the speaker terminals. Then the voice coil receives the current. When the current is running through the voice coil, the current creates a magnetic field. This magnetic field attracts and repels away from the magnet's magnetic field. The attraction and repulsion is based on the direction of the current. The voice coil which is attached to the cone will either push or pull the cone. The cone moving in and out is what causes the air to move or vibrate. The vibration in the air is what actually makes sound. This is how speakers work and subsequently how subwoofers work seeing as subwoofers are a type of speaker.
What differentiates nonsubwoofer speakers, is that these speakers can hit higher octaves.