A:Answer Compared to the Polk S55 speaker, the Polk S60 speaker has three Mid-Bass Transducers (vs two), supports 300 watts per channel (vs 200), and has a frequency response of 26 Hz - 40 kHz (vs 32 Hz - 40 kHz). The S55 is already substantial, but the S60 is 3 inches taller, 3 inches deeper, and 8 pounds heavier. I haven't tested them side-by-side. The S55 has been more than adequate for my needs.