A mid-range driver is called upon to handle the most significant part of the audible sound spectrum, the region where the most fundamentals emitted by musical instruments and, most importantly, the human voice, lie. This region contains sounds which are the most familiar to the human ear, and where discrepancies from faithful reproduction are most easily observed. It is therefore paramount that a mid-range driver of good quality be capable of low-distortion reproduction.The PRO-GM series midranges were designed after the GEN Series and tweaked to perfection, these speakers embody the beginning of DS18. The clarity and depth of the acoustics these midranges produce is only comparable to that of "the big bang." The pro-gm midranges feature black color steel baskets, Cloth edges, paper cones, and the option to choose between classic, bullet, or sealed back configuration. The PRO-GM line is one of the most sought out midranges in the industry for deal seeking audiophiles.