Some microphones will require phantom power in order to function. This is 48 volts of power that is sent via the XLR cable and this powers up the microphone and allows it to work.
Microphones that require phantom power are typically condenser microphones which use something known as a capacitor to pick up sound. This capacitor requires some voltage to operate and the audio boffins back in the old days decided that +48v was the standard voltage that all microphones should use to do this.
To enable phantom power on EVO 4, simply press the channel button you wish to use phantom power on and then press the 48v button. This will then remain lit red to remind you that you have phantom power on.
In rare cases, microphones can be damaged by providing phantom power to them so we’d always recommend checking the documentation for your microphone to see if you need to provide phantom power or not.