ipolar Tower Loudspeaker. With its high-performance patented bipolar sound array and integrated 8-inch powered subwoofer, the Definitive Technology BP9020 Tower Loudspeaker is your entry into bold cinema sound for your home. With unique technologies such as Forward Focused Bipolar Array, BDSS™ woofers, and an integrated 8” subwoofer, the BP9020 tower speaker brings you bold cinema sound for extraordinary home cinema experiences.