Steps for Removing Low-end Noise from Sound Effects for Video

Since commercial and corporate video production budgets can often be small and executed under a short time frame, the recorded sound may suffer. During post-production, as a result, producers may encounter some terrible audio problems. One common dilemma is a low-end noise or hum that permeates dialog and other ambiance recordings.

There are certainly many software plugins that remove noise and some work quite well. However these softwares often require a bit of study, which may impossible during a tight deadline. Instead, simply use the basic equalization and reverb plugins provided in your video or audio editing software.

Use standard package plugins and the following tips to eradicate nasty noise from the bottom end of your audio recordings:

Use a Single Band EQ first to cut out the unwanted rumble. A single band EQ will filter out all audio above or below a specified frequency. You can cut out, for example, all frequencies below 80 Hz in order to erase much of the rumble, which occurs at 60 Hz, without harming dialog tracks.

Secondly, a Parametric EQ can be used to "notch out" the unwanted noise by decreasing a thin width of audio frequencies and its octaves such as 60 Hz, 120 Hz, and 240 Hz. The advantage of using a Parametric EQ is that one can notch out the offensive noise without hurting wanted audio.

Third, use a Parametric EQ to boost the desired audio slightly. By doing so, it will be prominent over the noise and take the listeners attention away from the unwanted hum. For example, boost a bit at 5 Khz to raise the human voice over a low hum.

Finally, one can use reverb on the entire mix once the lower rumble has been cut out. This can reduce the "tin can" effect that might result from minimizing the lower end.

While the above tips are very basic and will not by any means eliminate the problems of poorly recorded audio, they will definitely improve the sound of a poor recording when the dialog and hum are vying for the listener's ear.

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