How to Remove Background Noise from Voice Recordings Pt.2

We learned how to recognize background noise in our voice recordings in the previous post.

That might be your audiobook recording, podcast or a voice recording for video...

We talked about where background noise comes from, what it sounds like and what it looks like in iZotope RX in Part 1.

Let's continue on and introduce the spectral de-noise module in RX (using the standalone audio editor).

What makes it so special and when should you use it in the process of cleaning up your dialogue recordings?

How It Helps Your Audio

When it comes to background noise in your dialogue recordings, the spectral de-noise module shines.

It's very effective, it's adaptable to a wide variety of background noise problems and it's quick to use once you become familiar with it.

And I'll help you become very familiar with a clear, repeatable workflow to use it quickly in this series.

Because of its effectiveness and adaptability, I've used it to deal with background noise in all of my clients' and all of my own dialogue recordings. 

When it's set up to address your specific noise problem, it clears out the noise beautifully.

It handles hiss, hum, rumble and more with dexterity. It just gets the job done which is indispensable when you're on a tight schedule.

Finally, it saves you time because this module, unlike some others in RX, works over your entire recording.

Once it's dialed in correctly, you can let the spectral de-noise tool run a pass over the whole dialogue recording to remove the noise in one go.

No need to spend time combing through your voice recording to treat bad spots!

^{(Spectral de-noise dialed in for hiss in my voice-over project)}

Why It's Better Than A Noise Gate

Another reason why the spectral de-noise module is so special when it comes to removing background noise is because it works more effectively than a noise gate.

A noise gate is an audio tool that could be thought of like an actual gate. It opens and closes to let sound pass through or to stop sound from passing through.

Noise gates are used in dialogue recordings to deal with background noise, but the results are not as clean and clear as the spectral de-noiser.

In my experience, the noise gate only removes noise between phrases (and even there, it leaves some unwanted noise behind - called artifacts).

But, the spectral de-noise module removes noise between phrases more cleanly and actually removes noise DURING phrases (while you are talking)!

To show you the difference, look at the images of the same section of my voice-over project using a noise gate versus the spectral de-noise module (below):

• where you see the blue waveforms are areas of talking (the phrases)...
  
  
• between the blue waveforms are the start or end of phrases (silence or breaths)...
  
  
• in the "Noise Gate" example, the bluish orange haze seen mostly above the blue waveforms is background noise...
  
  
• notice in the "Spectral De-noise" example how the haze has largely disappeared above the phrases (the talking)...
  
  
• this is the removal of the background noise while minimally affecting your dialogue!

 [ Noise Gate ]

 [ Spectral De-noise ]

Something that can't be seen in the images above is how spectral de-noise beats the noise gate in the gaps between the phrases as well.

If you were to listen to the two examples above you would hear:

• that the "Noise Gate" example leaves high frequency noises at the end of phrases when the noise gate is closing...
  
  
• HOWEVER, the "Spectral De-noise" does a much better job with a clear and natural sound between phrases!

When To Use It

In an earlier post, we talked about how I use spectral de-noise before RX's documentation suggests it should be used.

That's because de-noising a dialogue recording early on has helped me uncover clicks, pops and mouth noises that were hidden by the background noise.

Further, I regularly use spectral de-noise before some other steps in the editing process and haven't noticed any degradation in overall sound quality.

So I don't mind suggesting you use it the same way, if you're ordering the clean-up of your voice recordings roughly how I'm doing it:

• full pass for mouth noises
  
  
• full pass for background noise
   
• full pass with noise gate to clean between phrases
  
  
• full pass for sibilance
  
  
• one go of systematically working through entire recording for remaining trouble spots
  
  
• removing resonances and sweetening
  
  
• mastering for final release

On the other hand, you may find a different way that works for you... Maybe you're pressed for time and can only run full passes for cleaning your dialogue audio. No worries!

My goal for you is not to be bound to my specific procedures or anyone’s specific tools, but to help you train your ears.

Then, in your listening, you'll be able to make your own decisions about what works best for your situation.

As always, let your ears be the guide!

Summary

Remember, the spectral de-noise module in RX is a very valuable tool for cleaning up your voice recordings. That's because it's effective, it's adaptable and it's quick to use.

Further, another reason to like the spectral de-noiser is because it works more effectively than a noise gate (the more common tool to deal with background noise).

Finally, you can use it fairly early in the editing process to reveal problem noises that were hidden by the background noise.

However, don't feel the need to be bound to my specific procedures or anyone’s specific tools, but go by what your ears are telling you!

In this way, you'll be able to make your own decisions about what works best for your situation.

What other suggestions do you have for dealing with background noise in your voice recordings?

Would love to hear your thoughts below!

Cheers, Bryan
Your Dialogue Editing Mentor