The subwoofer has two oval 356×15 mm diffusers with an effective area of each approximately corresponding to an 8-inch woofer. The radiators are included in a bipolar circuit, and their flat diffusers are actually front and back panels. The diffusers have unusual spiral suspensions that allow them to move forward with a large amplitude. For excellent bass clarity, striking in its power and depth, the subwoofer has a 900-watt Ultra D class amplifier, and the low-frequency range starts at 21 Hz.