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Learn Music and Audio Production | iZotope Tips and Tutorials

How to Remove Background Noise from Dialogue Recordings

by Audrey Martinovich, iZotope Contributor September 6, 2022

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Few things can be as distracting as background noise. Whether you need to clean up a voice over for video content, dialogue that was recorded on a film set, or are producing a podcast from home, here are a couple of workflows to remove background noise from a recording.

Jump to these sections to remove background noise from dialogue:

Follow along with this tutorial using the new RX 10, the smart solution for clear audio.

Identify audio problems, then tailor your approach

Background noise in your audio is not only a distraction, but can make it tricky to boost quiet passages without also boosting the volume of the background noise. When removing background noise from dialogue or other audio, start by evaluating the noise. Is the noise constant, like the hum of an air conditioner, or something more intermittent such as a dog bark? This distinction alone will help you decide which tools to use to remove the noise. 

To demonstrate the workflow for either scenario, I have two scenes from a short film as examples. One scene was recorded in a restaurant with an audible low hum from the air conditioning system. In the other scene, a thump caused by a boom pole bumping into a wall can be heard. Keep in mind: a good rule of thumb for avoiding artifacts with audio cleanup is to take small steps toward your goal, using a couple of passes of gentle processing, rather than denoising with more dramatic settings.

Workflow to remove steady background noise

  1. This workflow works well for cleaning up audio problems that occur regularly through your audio like harsh esses, hiss, hum, excess reverb, or frequent mouth clicks by allowing you to process your audio in its entirety.
  2. Open the audio file in the RX Audio Editor or send it via RX Connect, then open Dialogue Isolate. Or within your DAW, open Dialogue Isolate as an Audiosuite plugin and select your audio. 
  3. Click on the Preset Manager in Dialogue Isolate to audition some presets that might work for your specific case. In this example, I’ve used “General Dialog Cleanup” as my starting point.
  4. Adjust the Sensitivity to your liking. I like to bump up the sensitivity to where I start to hear some artifacts creep in, then lower it back down a bit to find the point of maximum cleanup without introducing problems. 
  5. Adjust the Ambience Preservation to make sure there’s no unnatural gating of the room tone or awkward ambience shifts during quiet parts.
  6. Render your audio once you’re happy with the sound.
  7. After your first pass of audio cleanup, you might notice new issues that need attention. In this case, without the low hum of the restaurant, the speaker’s esses sound more harsh so I decided to tame them with RX De-ess
  8. Once you’ve opened the De-ess module, select a bit of audio with lots of esses. Preview the audio and lower the Threshold to tame esses until it sounds like we introduce a bit of a lisp, then raise it back up to find the happy medium. This is similar to what we did earlier when we raised and lowered the Sensitivity in Dialogue Isolate to find the perfect amount of processing.
  9. Render your selection once you’re happy with the results.
iZotope RX Dialogue Isolate in a session can help remove steady background noise from audio
iZotope RX Dialogue Isolate in a session can help remove steady background noise from audio

Workflow to remove random background noises 

This workflow works well for cleaning up audio problems that happen randomly through your audio like a door slam, dog bark, chair squeak, etc. These noises are intermittent and can have very different noise profiles so it’s best to address these spots individually rather than processing your entire track. In this case, there is an audible thump from the end of the boom pole bumping into a wall that we will remove.

  1. Open the audio file in the RX Audio Editor or send it via RX Connect
  2. Listen to your audio while looking at the spectrogram to find where the problem occurs. In this example, we can see a clear transient by looking at the blue waveform, but we can also see that this thump consists of mostly low end content by looking at the orange spectrogram. The brighter the orange, the louder that frequency.
  3. Using the lasso tool, draw a shape around your noise on the spectrogram and open the Spectral Repair module.
  4. Spectral Repair allows you to Attenuate, or turn down the sound, Replace, which removes the trouble audio then fills in the gap with audio that comes before and after the problem spot, Pattern, which replaces the audio selection with similar audio found elsewhere in your file, and Partials + Noise which finds harmonics and noises from either side of your selection and uses that in place of the noise we want to remove. 
  5. Try out a couple of different approaches to find what works best for your noise. In this case, I used Pattern, but I often have great success using Replace to remove sounds of noisy audience members that distract from a choir sustaining a soft note. Use the Compare function to audition different settings and find what works for you.
  6. Once you find a setting that removes the background noise without introducing any artifacts, hit Render.
  7. If you’re using RX Connect, click Send Back to return to working in your DAW. 
  8. Press Render to commit the changes to your audio.
RX Spectral Repair spectrogram before noise reduction
RX Spectral Repair spectrogram before noise reduction
RX Spectral Repair spectrogram after noise reduction
RX Spectral Repair spectrogram after noise reduction

Start removing background noise from dialogue 

There are as many ways to remove noises from dialogue as there are noises, but there isn’t much you can’t remove if you go about it in the right way. Removing steady issues first with gentle settings rather than dramatic settings, such as having the Sensitivity in Dialogue Isolate turned all the way up, will almost always give you a more natural sounding result. Then, you can zoom in to the moments when noises occur and remove those individually, tailoring your approach to that specific sound. 

Download iZotope RX and start removing distractions from your dialog recordings today!

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