You really don't have much of a choice. Any modern Audio Video reciever has a low voltage LFE (low frequency effects) or sub output. The only thing that has passive subwoofer outputs are home theater in a box setups that include the AVR and usually 5 speakers and a sub. Avoid these at all costs.
One more thing, don't get cheap with a subwoofer. The LFE channel is extremely important. Cabinet size, cost and output are directly related to room size. For a typical open Floorplan designer home in The Villages, most are over 8000 cubic feet and require a large subwoofer to get reference level bass at the lowest frequency.
I sell a couple different lines of Subwoofers including
www.SVSound.com. Bang for the buck you can't do any better PERIOD. You are welcome to stop by and have a look (and listen) for yourself.