The 13" electro-magnetic stackable passive subwoofer offers dual large diameter front ports. The Sub Utopia EM is the last building block of the Utopia 3 range and the logical follow-up to the ultimate multi-channel reference speaker Viva Utopia. With this subwoofer, Focal focused all its know-how on an entirely passive design, based around a 13-inch electromagnet bass driver, that appeared with the Grande Utopia EM. An ideal complement to the Viva Utopia, this subwoofer can be used with any model of the range, including the Grande Utopia EM.