I know from personal experience it can get loud at the Kohl Center. From my post atop Bascom Hill, I could hear the roar of the crowd when the Badger men’s basketball team beat Illinois in 2003 to win the Big Ten Championship. Celebrating its 10th anniversary in January 2008, the Kohl Center continues to be a winning venue for the Badger hoopsters — its home game record under Bo Ryan is 104-6 (as of Jan. 31, 2008).
The Kohl Center’s cantilevered balconies were unique at the time of construction in 1998, when most arenas were built with a main seating bowl and one large balcony with many rows. At the Kohl Center, the number of balcony rows was roughly divided, creating a shallow first balcony and then stacking the remaining rows above on a second balcony. Similar to the Fieldhouse, this brings more fans closer — and thus, more crowd noise — to the court.
The cinder block you mention is indeed “acoustical block” and is designed to absorb some noise via the insulation in the slots. The underside of the roof, made of perforated acoustical metal deck, also has absorptive properties. Without these features, the reverberation of a certain frequency of sound would be distracting.