YAMAHA Q2031B STEREO GRAPHIC EQUALISER The Q2031B is a sophisticated stereo 31 band Graphic Equaliser. It provides 6dB or 12dB of Boost or Cut at ISO third octave frequencies from 20Hz to 20kHz. A High Pass Filter can be switched in which attenuates at 12dB/octave below 200Hz. Ins and outs via balanced XLRs and unbalanced Jacks. Note. The Q2031B is 2U high because it is not possible to get detailed slider resolution from a unit 1U high.