Drag the recorded audio file into your audio editing program. This will import the audio and prepare it for the singing editing process.
Find a few seconds of pure noise with no music playing in the audio file. Highlight three seconds of noise. Click the "Effect" menu or equivalent menu in your program, and then select "Remove Noise" or "Noise Removal." Click the "Get Noise Profile" option and then click okay. Select the "Noise Removal" drop-down option again and this time, press OK. This will remove any excess noise in the file allowing the voice to come through.
Select the "Effect" menu and then click on the "Normalize" option from the drop-down menu. Leave the options in the default setting and click "OK." This will increase the volume of the recording to the loudest setting without distorting the audio.
Use the "Compressor" option, usually found in the "Effect" menu to compress the contents of the audio file and make the voice sound fuller. Leave all of the options at the default setting and click "OK" in the compressor dialog box.