SIGMA 8 uses the latest in Wharfedale Pro driver technology for the LF drivers, engineers have incorporated a curve linear, double-roll surround for smooth mid-high transitions and stability for low through to mid range frequencies. The 1 inch polymer diaphragm HF driver is equally robust in design using a solid aluminum rear plate, the HF driver is strengthened for durability and heat is dissipated efficiently for demanding environments. Wharfedale Pro engineers have selected a 90° x 60° elliptical wave guide optimized for wide coverage for fixed installation purposes.