The GT-1's on-board Noise Suppressor is the component in the GT-1 version of BOSS Tone Studio named "NS".
To get to it:
- Press MEMORY EDIT.
- Turn Knob 1 until NS is selected.
- Press ENTER.
- Using Knobs 1, 2 and 3, you can adjust the Noise Suppressor's Parameters to the desired settings.
- Save your changes to the Preset.
For more detailed information on the Noise Suppressor's Parameter. Please consult the GT-1's Parameter Guide here: https://www.boss.info/global/products/gt-1/support/