dbx 231s Dual 31-Band Graphic EqualizerWith 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. 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. The dbx 231s includes two 31 band channels of 1 3 octave equalization, 12 dB input gain,