If you have unwanted background noise in a song, interview, or any kind of digital audio file, you can easily remove at least most of it with Audacity, an audio editing program that you can download for free. This process will only work for segments of audio where the sound that you want to keep is absent, such as a pause in a sentence or a moment of what you want to be complete silence in a song.
Open your audio file in Audacity.
Highlight the initial portion of your audio file that contains the unwanted tape hiss, fan noise, hum, or other kind of noise that you want to eliminate. You will have to zoom in considerably on the sound wave to make your edit exact.
Open the "Effects" menu, select "Noise Removal," and click "Get Profile." Audacity will then learn the kind of sound that you want removed.
Select the rest of the audio file and click the "Remove Noise" button. This will clean up the rest of your audio file.
Tips & Warnings
- This operation tends to result in some distortion, which cannot be avoided. The louder the background noise is in relation to the signal that you want to preserve, the greater the amount of distortion you will hear.