■ Vented subwoofer ■ Two 15" high powerful subwoofers with 4" voice coil. ■ Firm grille with perforated hexagon steel protecting the loudspeaker from outside force impact. ■ The enclosure uses high-density plywood and firm finish to protect it from friction and collision. ■ Acoustics buffer, high safety and sound quality ■ LF is powerful , deep and strong. ■ Used in local needing powerful LF energy compensation.Combining with DR68 full range series, working in the large scale sound reinforcement system.