Woofer is the term for a loudspeaker driver that is designed to produce low frequency sounds, typically from around 40 hertz up to a few hundred hertz. Today one can find woofers which can reproduce sounds as low as 20 Hz (the human ear detects a nominal range of 20 Hz to 20,000 Hz). Some woofers produce frequencies up to around 1000–2000 hertz and are usually called mid-woofers.

Nearly all woofers are driven by a voice coil in a magnetic field, and they typically have a diameter of 5 to 18 inches (125 to 460 mm).

The resonant frequency of the woofer is determined by the compliance (flexibility) of the cone suspension, the mass of the cone, the magnetic field strength, and the air resistance behind it. The lower the resonant frequency, the lower the frequency of sound that may be produced without distortion.

The term woofer can also refer to a speaker driver and cabinet combination that produces low frequencies only. Since these low frequencies are essentially non-directional compared to higher ranges, the correct placement of a woofer-only cabinet for the best sound is much less critical, although placement in a room corner will noticably enhance the bass sound.

See also:

• Loudspeaker
• Tweeter
• Mid-range speaker
• Subwoofer