For your speakers I would recommend avoiding subwoofers and letting them run as they are.
They have 3 x 9 inch woofers and response down to 25Hz driven by a robust powerful amplifier. Unless you want to high pass filter your main speakers (not recommended) the subwoofers will contribute little additional content. Be aware that subwoofer integrations are a compromise and will introduce cancellation and dynamic issues that critical music listeners can detect.