Subwoofers are speakers designed to reproduce low frequencies, usually referred to as bass. There are two basic types of subwoofers: active and passive. Active subwoofers have their own amplifier integrated directly into the unit, while passive subwoofers require an external amplifier for power. Active subwoofers are often considered more user-friendly because they do not require additional equipment to function, while passive subwoofers can provide a higher level of control over the sound.