The Yi-SUB is an actively driven cardioid subwoofer powered by a single amplifier channel. The Yi-SUB is the installation version of the Y-SUB and differs only in cabinet construction, finish and mounting hardware. It houses two long excursion neodymium drivers in an integrated cardioid setup, an 18” driver in a bass-reflex chamber facing to the front and a 12” driver in a two chamber bandpass design radiating towards the rear. The cardioid dispersion pattern resulting from this arrangement avoids the distribution of energy behind the system, providing the greatest accuracy of low frequency reproduction and reducing the energy dispersed into unwanted areas. The Yi-SUB is fitted with three point rigging hardware and can be flown in a column of purely Yi subwoofers, at the top of a Yi array or used in a ground stacked setup. The cabinet is constructed from marine plywood and has an impact resistant paint finish, whilst Weather Resistant and Special Colour versions are available. The front of the loudspeaker cabinet is protected by a rigid metal grill backed by an acoustically transparent foam.