The 300 Series features multiple upgrades over the entry-level 100 Series, all designed to improve both audio performance and aesthetics, befitting of its more premium status. The AE309 uses two latest generation 130mm mid-bass drive units. The result of this latest drive unit technology and enclosure design is a slim-line, powerful floor-standing loudspeaker for the discerning listener when refined audio quality coupled with elegant aesthetics are paramount.