While using the interface as your computer's audio output device, media keys on many systems may no longer work to adjust system audio volume.
Use the Monitor knob on the front panel of the interface to adjust volume.
Press the Inst button on the front panel to switch the corresponding input to high-impedance.
Turn up the Gain knob on the corresponding channel to set the amplification of your signal.
How to adjust my mic gain?
1) Try with another cable to see if it solves the issue.
2) If you are using a dynamic microphone, check the user manual of your microphone to see how much gain it requires. The MiniFuse is delivering a gain of 56dB.
3) If you are using a condenser microphone, check the user manual of your microphone to see if it needs phantom power. If so, press the 48v button, that will supply the required current to your microphone.
As you can tell from the picture below, there is only one switch for the 48V phantom power feature on the MiniFuse 4.
It means that the MiniFuse activates phantom power for both XLR inputs when the switch is on.
As a consequence, you are advised to only use this feature with microphones that require it.
If it is the case, make sure to turn off phantom power first, and then connect or disconnect the microphone. Do NOT connect or disconnect microphones while phantom power is ON.
Please note that the 48V phantom power does NOT affect the Jack cable connectors. You can then safely connect an instrument (a synthesizer or a guitar for example), while phantom power is activated for a microphone already plugged into the audio interface.
Warning: Phantom power may damage some equipment like certain ribbon microphones. Please check your equipment's user manual to determine if it is possible, AND necessary, to use a 48V phantom power source.