JBL 15 in low frequency driver with a 64 mm (2.5 in) diameter edgewound ribbon voice coil which provides more cross-sectional wire area in the voice coil gap than round wire designs, for greater efficiency and power handling. JBL 2414H-C 25 mm (1 in ) polymer diaphragm compression driver improves high frequency performance as well as system reliability. The advanced network topology crossover design shapes the frequency response to deliver coherent summation in the crossover region. High-voltage capacitors and inductors with massive cores and heavy gauge wire enable the crossover network to handle high power without saturating. Progressive Transition™ high frequency waveguide provides superior coverage control, reduced distortion, and smoother frequency response. The rugged, acoustically superior enclosure is constructed from 19 mm (.75 in ) MDF (Medium Density Fiberboard) using advanced adhesives and mechanical fastener technology for extreme durability and improved low-frequency performance. SonicGuard™ protects the high frequency driver from excess power without interrupting the performance. Non-resonant, all-steel handles are used. Attractive 18-gauge perforated, steel grille protects components from damage. Dual-angle pole-mount socket allows the speakers to tilt 10° for more uniform audience coverage.