Array speaker can be used in indoor and outdoor. Line array is a loudspeaker system that is made up of a number of usually identical loudspeaker elements mounted in a line and fed in phase, to create a near-line source of sound. The distance between adjacent drivers is close enough that they constructively interfere with each other to send sound waves farther than traditional loudspeakers. They are of slim design and wonderful sound effect. They are optical choice for conference and gathering parties.