Open System Preferences from the dock or the main Apple Menu.
Select the Sound preference icon, choose the Input tab and select Go Mic.
Set the gain of the Go Mic by adjusting the Input volume slider at the bottom of the Sound dialog box.
Set the Go Mic as playback volume by clicking the Output tab and select Go Mic, adjust the Output volume slider at the bottom of the Sound dialog box to the maximum setting and use the Go Mic’s front panel Volume knob to control the overall output from the headphones or speakers.
To turn direct monitoring on or off, open the Audio/MIDI Setup utility located in the Utility folder inside the Applications folder. Then click the check-box in the Thru column in Audio/MIDI Setup.