The Nakamichi Shockwafe Ultra 9.2 4 and 7.2 4 soundbars have a slight difference in the number of speakers. The Ultra 9.2 4 has nine speakers and two subwoofers, while the Ultra 7.2 4 has seven speakers and two subwoofers. The additional speakers in the Ultra 9.2 4 provide a more immersive sound experience and enhanced audio quality. Both soundbars support Dolby Atmos, which creates a three-dimensional sound field. They also come with wireless subwoofers for deep and powerful bass. The Ultra 9.2 4 and 7.2 4 soundbars are well-made and designed to deliver high-quality audio performance. They are easy to set up and don't take up much space in your home entertainment setup. Overall, the Ultra 9.2 4 offers a more premium sound experience with its additional speakers compared to the Ultra 7.2 4.