Rocktron Widowmaker Guitar Preamp Rack Mount Controls include Level, Bass, MID, Treble and Gain in the HIGH GAIN channel, and Level, Bass, Mid and Treble for the CLEAN channel In the HIGH GAIN Channel, the Level control determines the output level independent of the Clean Channel The Bass control is used to determine the amount of low frequency information present in the High Gain channel, and is adjustable to + -15dB The MID control in the High Gain channel is used to determine the amount of high frequency cut. Up to 30dB of mid-range cut may be applied The Treble control is used to determine the amount of high frequency information present in the High Gain channel, and is adjustable up to + -15dB