GRF Pro Audio Dance Stack Professional Speaker (MBL-18D)Features: 1. Compact size and unique design meets the requirements of invisible Large-Scale Activities2. Reflex structure. High efficiency and SPL, ultra low frequency, free dispersion. 3. Dual woofer and independent output, allows multi connection, cost effective. Applications: 1. Outdoor bass for line array system2. Large scale live concert and banquet hall3. Arenas, club and theater"DANCE STACK" is a sonically and visually imposing "stack" of matched components to provide the dance world. Fundamentally the dance stack is a five way system withsubbass, bass, mid-bass, mid and high frequency components. It use 24dB/octave crossover slopes and time alignment. Equalisation is not required. To make sure of the bass limit, there is a newly designed infra horn and 2 x 18"subwoofer dealing with the "weight" part of the bass. A pair of MBS-218 bring the "punch" of the bass, upward we have a newly designed MBL-18D as horn loaded 18" which works for the upper bass and 12" low mid. A new 8" provide the mid range power to match the exceptional bass limit combination. The remaining high frequencies are handled by our outstanding 1" compression driver. The system is applicable for ballroom, DISCO and a song and dance. This system can be combined with MBL series perfectly, be applicable in medium size room as the delay or filling system. The innovative hang-up system be applicable for all speakers of MBL serie and easy for installation. All hardware accessories for hang-up are inside of each cabinet, the system can be stacked on ground safely. This portable "full-range" system is probably the smallest fully horn loaded enclosure available. It's unique combination of compact size, wieght and sonic excellence, make it equally suited for use by discerning musicians as well as by sound consultants in demanding projects. From small to medium club venues to strict video and audio sound reinforcement applications. The loudspeaker system resolves the needs for quality, response and level from a small source. The serie is increasingly regarded as the DJ choice of monitor. If even more bass is required, the combination for a pair of MBL-15 can be used with a single subwoofer is seamless.