How to Clean Up Sound Effects by Removing Low-end Noise
Due to short time frames and small production budgets, audio for video is often not well recorded. As a result, certain unwanted noises often plague producers during post-production. A common noise in recorded audio for sound effects and dialog is an annoying hum or rumble at the bottom end.
Software plugins that remove noise from audio abound and some function very well. However, under a fast approaching deadline, one may not have the time to find, purchase, and learn the nuances of a new plugin. For these situations, simply turn to the default equalization and reverbs provided in your audio or video editing software.
Use these procedures in tandem with your default plugins to help rid your audio recording of unnecessary and distracting noise:
Initially you can try using a Single Band EQ to attempt to erase much, if not all, of the unwanted hum. Using such an EQ you can take away all the audio below or above a certain frequency. For instance, since a low end rumble from an air conditioner emits around 60 Hz then by placing a Single Band EQ at 80 Hz one can most likely eradicate most of the unwanted noise without damaging any voice 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.
Fourth, once the low end has been cut or minimized, use a bit of reverb on the entire mix. This creates a sonic wash of sorts and reduces the “tin can” effect that can be created by cutting out the low end.
By using the above tips, while they will not completely fix poorly recorded audio, one can vastly help the quality of a recording in which a undesirable low end frequency is compromising the other elements in an audio mix.
Filed under: Arts & Entertainment