A passive subwoofer contains only a woofer in an enclosure with no amplification. An active subwoofer contains an onboard amplifier that will accept a low-level input and usually contains electronic crossovers. A passive subwoofer must be powered by an external amplifier and connected via the speaker-level connection. Many times this passive subwoofer contains a built-in passive crossover that sends the bass to the subwoofer driver and passes the higher frequencies to the satellite speakers. This methodology is inherently difficult to implement and will usually result in very poor integration between the woofer and the satellites. Using an active subwoofer system will almost always provide superior results due to the greater control in matching output levels and matching the crossover point between the subwoofer and satellites.
What is the difference between an active and a passive subwoofer?
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