How to Remove Background Noise from Voice Recordings Pt.1

^{(Hear audio example in blue box)}

Persistent background noise in our voice recordings may not be as noticeable as something like stabbing sibilance or clipped audio that was recorded with levels too high.

However, it can still easily be heard behind our dialogue recordings, robbing them from sounding clear and intelligible.

It's a common problem, especially for those of us recording at home where you don't always have an ideal recording environment.

Thankfully iZotope RX has some powerful options to clean up background noise in our voice recordings.

And in this series I'll show you how to clear out that background noise with a few easy steps.

But first, before you can start clearing, what are some ways to recognize background noise in your voice-over, audiobook or sermon recordings?

What Is Background Noise?

When we're recording in less than ideal environments, annoying background noise can come from a variety of sources.

Things like computer fans, air conditioners and heaters, nearby highways and train tracks, refrigerators and electrical interference from lights are common offenders.

When we talk about background noise in your voice recordings, we're talking about unwanted, persistent sound at a lower level than your spoken words.

The background noise could have a pitch (an example would be hum) or it may cover multiple frequencies (an example would be hiss).

It could also have both of these "qualities" if you're dealing with noise that includes hum, hiss and a problem like rumble.

The good news is that the spectral de-noise module in RX can quickly and beautifully handle all these types of background noise making it one my favorite modules in all of RX.

What Does It Sound Like?

What then, do you listen for to recognize these types of background noise?

We're not so much interested in sounds like the sudden barking of a perturbed dog or the inopportune passing of a noisy delivery truck here.

Nonetheless, RX's spectral de-noise can most likely deal with those too if you can get a clean sample of just the noise.

What we're trying to hear is the low-level, constant noise throughout our dialogue recordings.

I've got two examples of some typical background noise to help you become familiar with the sound.

Prepare to be underwhelmed (since you're listening to noise after all)...

Listen to the audio example (at top of page in blue box) to hear persistent background noise from my voice-over project:

• these have been separated from the spoken words and the volume boosted to clearly hear the noise.
  
  

What Does It Look Like?

Seeing the background noise in iZotope RX's display can be a bit challenging.

This is because the noise is at a lower volume (in the background) and will not be as prominently displayed as louder sounds (which will be brighter colored).

To help you learn to spot the background noise, I have "before" and "after" examples of the same section of my voice-over project below.

• the "after" example shows the noise decreased using the spectral de-noise module...
  
  
• if you look closely, you'll notice where an orange haze has disappeared in the "after" image...
  
  
• that orange haze is the background noise!
  
  

In the "after" image, look above, below and in between the blue waveforms to see the background noise removed:

 [ BEFORE ]

[ AFTER ]

Summary

Remember, background noise in voice recordings is unwanted, constant sound at a low volume picked up during recording from something like a computer fan.

Next, this kind of noise tends to sound like a persistent hiss or humming sound or even a low rumbling noise.

Finally, background noise can be hard to spot in RX's display because it's at a lower volume. Look for a general orange haze all around your waveform in the display to track it down.

Have YOU used these concepts on a dialogue recording to find noise? How did they help? Leave a comment below.

Cheers, Bryan
Your Dialogue Editing Mentor