A line array is made up of a column of identical line array speakers that are stacked vertically. This produces more volume as well as preventing acoustic problems like unwanted reverb created by reflections. Line arrays often have a subwoofer on the bottom that takes care of the bass, while the speakers are placed above or on top of the subwoofer. These days, there are portable mini line array systems on the market too which are essentially full PA systems. Most are portable, attractively-priced and consist of a (built-in) mixer, an amplifier, speakers and a subwoofer.
