SB15m is the recommended subwoofer for the KIVA system and the XT coaxial series. It allows extending the system operating frequency range down to 40Hz. SB15m features one direct radiating 15-inch speaker in a bass reflex tuned enclosure. It provides impact, sensitivity, low thermal compression and reduced distortion. The vent features a progressive profile allowing laminar airflow and reduced turbulence noise even at the highest operating levels.