Connect the female end of an XLR cable to the bottom of a microphone. Connect the other end of that microphone cable to the "XLR Input" jack on the front of an audio interface.
Connect the interface to your computer. The method of connection varies according to the make and model of your audio interface. Typically you'll need either a Firewire or USB cable.
Double-click the desktop icon to open your preferred digital audio workstation, for example Pro Tools or Cubase.
Launch a new session with the workstation. The exact process varies according to which program you use, but you can typically execute this command from the file menu. For example, in Logic, click "File," "Open New."
Open an audio channel. The process varies, but you typically do this via the file menu. Digital audio workstations typically have tabs for this command, too. Look for a tab in the audio channel strip section with a "+" or "New."
Audition the microphone input level. Sing into it as loudly as you can. If the volume units meter goes above "0-db," reduce the "Gain" dial on the front of the interface. The input level must be lower than "0-db," otherwise distortion occurs. If this does happen, the meter will begin flashing a warning.
Click the "R" icon on the audio channel. This readies the channel for recording and assigns the audio interface as the primary interface.
Click "Record" and deliver the vocal, for example, voice-over or song.
Click "Stop" when finished and open the compressor tool. This tool enables you to cut the volume peaks, giving further headroom and enabling you to boost the base volume of the recording. You can typically access the compressor via the "Effects" menu.
Set the "Threshold" dial to about 50 percent. This reduces the gain of anything in the upper half of the volume spectrum.
Click "Output Gain" and select "+5-db." This scales the vocal audio by the necessary amount to take five decibels above zero decibels. Zero decibels isn't silent; it is a universal reference point for standard gain input level.