DBX 231 Two 31-band Graphic EqualizerThe DBX 231 Two 31-band, 2/3-octave, Constant Q Frequency Bands, Xlr And Trs Inputs And Outputs, Switchable Boost/cut Ranges Of ±6 Or ±12 Db. Simple to use dual channel EQ, ideal in the studio, on tour and with installed sound venues.The DBX 231 has been designed to meet the needs of the most demanding sound reinforcement environments, while offering the simplicity of straight forward controls. The 231 not only provides standard features like dual channels, 31 1/3 octave bands, ISO frequency meters, +/- 12dB input gain range, and switchable 40Hz/12dB octave low-cut filters, but also includes other thoughtful features. These features include: 20 mm faders; selectable +/-6dB or +/-12dB boost/cut range for precise gain adjustments; XLR, and 1/4 inch TRS (jack) connectors for installation ease; balanced inputs and outputs for quiet operation; and chassis/signal ground lift capabilities for quick hum isolation. The visionary design of the Dbx 2-Series has been pursued to make your job easier.