\rYou will need an amplifier to power your subwoofer in some fashion or another. There are two ways to do it. You can buy a subwoofer or a loaded enclosure and use an external amplifier to give the subwoofer the power it needs to perform. The other option is to choose\ra powered subwoofer enclosure where the amplifier is built-in to the subwoofer enclosure. Either way, you will still need an amplifier.\r