The IL 118 Sub is a subwoofer designed to extend the low-range frequency response of HK Audio IL 12.1, IL 12.2, IL 15.1 and IL 15.2 cabinets. It is loaded with a direct-radiating 18" cone loudspeaker housed in a bass reflex enclosure. The IL 118 Sub delivers powerful, low-ranging and dynamic bottom-end response. It is ideally suited for any application in which a sound system requires low-frequency reinforcement for coverage of distances up to some 20 meters, depending on the given sound pressure requirements. The IL 118 Sub must be operated in combination with an outboard active crossover or a hi-cut filter. The HK Audio Digital Field Controller (DFC) is recommended for larger and more complex application scenarios.