Graphic equalizer   

A device or software “plug-in” consisting of series of overlapping bandpass or band reject filters with fixed bandwidths, slopes and centre frequencies The software versions may have all of the parameters user controllable. 

professional devices usually have 31 “bands” or filters whose centre frequencies are arranged 1/3 octave apart with the capability of amplifying or attenuating the signal by + or - 12 dB. 

1/3 octave filter: each band has +/- 12 dB boost or cut.