How to remove background noise using phase invertion
Background noise in quiet parts of a recording are easily removed by either cutting it out manually, or by using a gate. But removing noise that's being heard at the same time as your target audio is a different beast.
Phase inversion is a process that can be used to remove background noise from a recording. This technique is often used in audio production, and can be very effective at cleaning up audio recordings.
To phase invert a recording, you will need to first identify the dominant noise source in the recording. This can be done by using a spectrum analyzer, or by listening to the recording and trying to identify the strongest noise component. Once you have identified the dominant noise source, you will need to create an inverted version of that signal. This can be done with a signal generator, or by using a software plugin. Most DAW's have a built in function for phase invertion.
Once you have created an inverted version of the dominant noise source, you will need to mix this signal with the original recording, either by having them play at the same time on separate tracks, or by using a software plugin tailored to this purpose. The inverted signal will cancel out the background noise, leaving you with a clean recording.
This may sound like magic, but this is how audio works. Read this guide for more detailed information on how to work with phase in audio production.
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