Soundmasking EqualizerModel No. EQ1 is a single channel 30 band Constant Q graphic equalizer with thirty 20mm center detented linear sliders on ISO center frequencies. The front features an overall level control (rotary), 12dB or 6dB range selector switch, overload clipping light, LED EQ bypass switch, and LED power indicator. The rear includes balanced unbalanced XLR and 1 4 TRS phone plug inputs and outputs. Polarity convention is per IEC ANSI AES standards of pin 2