1. S-18+ ultra-low frequency speaker is composed of an 18-inch high performance, high power and long stroke bass unit of 220 magnetic steel with a 100-core voice coil. Enclosure structure adopted direct type design, combined with their German audio technology, make its low frequency high performance, plump and soft, deep, powerful and rich flexibility, sound field include feeling is wonderful, good overall lower limit, tone is pure natural, rich music rhythm, has very good resistance to listen to, provide the audience with a steady stream of low frequency. With the full frequency speaker will achieve the most ideal effect. 2: applicable venue: bar, Disco hall, slow swing bar, entertainment KTV rooms of ultra-low frequency speakers, nightclubs, dance halls, clubs, medium-sized mobile performance of the main ultra-low frequency expansion, conference hall, multi-function hall of the main ultra-low frequency expansion.