A dbx double equalizer, likely a model like the 231s, is a professional audio device that provides two channels of 31-band, 1/3-octave equalization. Key details include switchable ±6 dB or ±12 dB boost/cut ranges, a ±12 dB input gain control, and 4-segment LED ladders for output level monitoring. It features robust construction with 20mm sliders and offers connectivity via XLR and 1/4" inputs/outputs.