A loudspeaker that reproduces the lower end of the audio spectrum (the bass frequencies). A subwoofer system includes a crossover circuit that filters frequencies around 100Hz and under to the driver while the higher frequencies reach the left, right and center speakers. In a home theater, the placement of all speakers is critical to the listener, but subwoofers are non-directional and can be located in a convenient spot, although corners are not recommended.
Passive and Active Subwoofers
Passive subwoofers contain only the speaker (the driver) and crossover. Active subwoofers are self-powered with their own amplifier. See
woofer.