If your Denon AV receiver has an LFE subwoofer output and possibly a calibration microphone your connectivity could be as simple as a single (inexpensive custom length RCA cable such as Blue Jeans Cable) to most any subwoofer with an RCA input.
IMO any subwoofer/s properly located and adjusted will add a new level of satisfaction.
IMO any subwoofer/s properly located and adjusted will add a new level of satisfaction.