DBX 231SV 2 Series - Dual 31 Band Graphic EqualizerExceptional sound and rugged reliability When the pros need an EQ, they turn to dbx. With a proven track record that spans four decades, dbx EQs are the industry standard for touring, studios, and audio installations. With the dbx heritage of revered pro EQs, the 231s meets the needs of the most demanding sound reinforcement environments, while offering the simplicity of straightforward controls. The dbx 231s includes two 31 band channels of 1 3