dbx 131s Single 31-Band Graphic EqualizerWhen 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 131s meets the needs of the most demanding sound reinforcement environments, while offering the simplicity of straightforward controls. The dbx 131s includes a single 31 band channel of 1 3 octave equalization, 12 dB input gain,