Connect the microphone to your input device, and boot up the computer. Start Pro Tools, and create a new audio track.
Enable the record mode on your new track, and press the record and play buttons on the transport bar. Record a test take of your vocal part, so you can set the controls on the effects units for a live take.
Open the mixer view by using the "Window" menu on the top toolbar. Locate your new audio track, and click on the first of the "dot" buttons in the upper part of the channel strip. Select your noise gate from the drop-down menu. Select the equalizer from the following dot button, and the compressor from the third.
Double-click on the noise gate button to open the editor. Adjust the threshold control until only the background noise is cut out from the signal. If you turn up the threshold to full, the gate will not engage. If you turn it all the way down, it will block everything. So find the "sweet spot" where the background hiss is removed, without detracting from the main vocal part.
Double-click on the Equalizer dot to open the interface. Engage the analyzer so you can see the frequency range of the recorded vocal. Cut the frequencies at both ends of the frequency range by engaging the high-pass and low-pass bands at the top and bottom of the Equalizer. Roll the frequency controls until they closely bracket the band that the vocal occupies.
Double-click the Compressor dot. The best setting will vary with each piece of audio, and the overall effect is very subtle. For a fairly average setting, adjust the threshold control until you can see the reduction meter showing approximately 50 percent. Adjust the ratio control until the vocal sounds smooth and balanced.
Delete your test track, and go for your live take of the vocal. Plug-in settings can be adjusted after the take, for fine-tuning purposes.