The Phonic PEQ3600 is a dual channel, 31-band equalizer that offers 12 dB of cut or boost in 1/3 octave steps, with standard ISO center frequencies between 20 Hz and 20 KHz. The Phonic PEQ3600 is a dual channel, 31-band equalizer that offers 12 dB of cut or boost in 1 / 3 octave steps, with standard ISO center frequencies between 20 Hz and 20 KHz. PEQ3600 is 2-rack space unit, and accepts both 1/4" jacks and XLR connectors. PEQ3600 is 2-rack space unit, and accepts both 1 / 4" jacks and XLR connectors.