How to Clean Audio Files

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There are many factors that can dirty up an audio file. Common issues include distortion, electrical hum, background noise and equipment deficiencies. Sometimes these issues can get so bad that they compromise the integrity of the audio file. There are several tools you can use to clean up audio files in just about every audio program, from free software like Audacity to professional audio software like Pro Tools.

Use EQ on your file to remove the unwanted frequencies. Noise is usually most offensive in the lowest and highest frequencies. A basic high-pass filter can remove a lot of low-end noise, such as 60-hertz hum. A low-pass filter can remove a lot of the harshness in static-like noises. Tweak your EQ so that you remove the noise without negatively affecting the sound that you want.

Try noise reduction software or plug-ins. Most audio programs have some sort of noise reduction built in. Some of the plug-ins will work in real-time, meaning that you will put the plug-in on the track with your audio file and adjust the plug-in so that the noise gets reduced. Other plug-ins don’t work in real-time. They require you to select a portion of noise and capture it. The plug-in then processes that noise and removes it from the entire file.

Gate or expand your audio file. Gates and expanders are plug-ins you can use in most audio software. Gating will silence the audio file whenever it falls below a certain level. This will clean up the audio file but may give it an unnatural sound. Expanding is similar to gating but instead of silencing the audio file, it reduces the level by a determined amount. Expanding will not remove all of the noise but it will turn the noise down and may preserve the integrity of your file better than gating. Spend some time setting the threshold of your gate or expander. The threshold determines at what level the gate or expander kicks in.

Edit out the messy parts. If you just need to clean up a cough or other unwanted sound in the middle of a file, you can import it into a program like Audacity or Pro Tools and just cut out the offending part. You can then export the file without the offending noise present. Be sure to use fades when you edit out noise to make the edits seamless.

Try compression to even out the sound. Compression won’t clean up any noise, and it can actually bring out the noise even more, but if you are having issues with consistency, compression can help even out a file dynamically and make it sound much cleaner.