The cabinet is cast from Estelon's proprietary marble-based composite, so its shape can be as complex as required - the Extreme has not a single flat wall, and each driver is housed in its own chamber. The crossovers are also placed in isolated compartments. The driver complement consists of custom Accuton CELL units with diamond domes for the treble, ceramic for the midrange and 250 mm aluminium sandwich cones for the bass - the stiffest diaphragms the industry can offer today. The price of such an uncompromising approach is an impedance dipping to 2 ohms and a weight of 250 kg per channel, so the amplifier needs plenty of current in reserve.