How to Remove Background Noise from Voice Recordings Pt.7

In the preceding post, we learned a huge time saving technique using a noise gate after noise reduction to clear background noise in dialogue voice recordings.

Along with that technique in part 6, we learned the simple step by step method to use a noise reduction tool like RX's de-noiser in part 5.

However, what if you need to clean up background noise from your audiobook, podcast or sermon audio, but don't have access to iZotope RX's wonderful, but pricey, spectral de-noiser?

Could a noise gate do the trick?

You may have noticed there are plenty of free noise gate plug-ins available to everyone online.

Is it possible to use just a noise gate for removing background noise in a dialogue voice recording?

When Would a Noise Gate Work Best?

Even though it isn't my first choice for cleaning up constant background noise, a noise gate can do a lot of good in clearing out a voice recording.

Especially in certain situations...

In the situation where:

• you've made sure your recording space is quiet...
  
  
• and you're getting a clear sounding recording to start with...

You have a case where you could probably just use a gate.

While recording, make sure you're not picking up any kind of hum and that any persistent noise from things like computer fans, air conditioners or refrigerators is as minimal as possible.

In this kind of situation you may only have a small or medium amount of background noise that's noticeable in the gaps between phrases of spoken words.

And a noise gate will really work well in this case to just touch up an already fairly quiet dialogue voice recording.

Essentially, the gate would be used to clamp down or close on any constant background noise in the spaces between your spoken phrases.

However, be aware that it won't be able to help with noise while you're speaking.

Here's an image of the gate I use on my voice-over recordings (see gate in red box below).

This one's not free, so look below if you need some FREE noise gate options.

^{[ Noise gate section of brainworx console N ]}

What If Your Recording Isn't Quiet?

That all sounds nice in theory, you might say, but my recording space just isn't very quiet...

You may have to record in a setting where there's some background noise even though your spoken words still come through pretty clearly in the recording.

In this situation and considering that you don't have access to RX's denoiser, a noise gate will probably be better than nothing...

If the background noise in your recording is noticeable and distracting during pauses in speaking, using a gate will probably be the way to go.

When you set up the gate to sound as "invisible" as possible, you'll have much quieter and less distracting gaps in between your spoken phrases.

Just make sure that the background noise occurring while you speak is not too noticeable (that it's pretty well obscured by the spoken words).

With that in mind, it's good to recognize that using only a noise gate for background noise will probably involve some sort of compromise in the overall quality of your dialogue:

• remember that the noise gate can't do anything to help noise that's happening while you're speaking...
  
  
• and beyond that, the noise will increase in volume in the finalizing or mastering stage when the overall volume of the recording comes up...
  
  
• therefore, this louder noise during speaking may or may not end up being a problem later down the line.

^{[ Background noise from an air conditioner ]}

Not to be confusing, but there are other times where a gate has been used for background noise, but the sound of it working is actually MORE noticeable than the noise was.

In this scenario, you can hear the noise between phrases cutting out unnaturally despite efforts to make it unnoticeable.

If the background noise isn't too apparent overall, this may be a case where you don't use a noise gate at all - audio can be confusing sometimes!

This is where careful listening can really light the way as far as what to do in different situations.

My goal for you is not to be bound by 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 in improving your voice recordings - let your ears be the guide! 

Setting Up a Free Noise Gate

There are many free noise gate plug-ins out there, but here are some that I've heard good things about or have used myself:

• Dead Duck Gate (and effects suite) | Gate Manual | Extensive Suite Manual
  
  
• ToneLib Noise Reducer
  
  
• Renegate

Let's learn to use the Dead Duck Noise Gate to remove background noise in a dialogue voice recording (settings from my voice-over for video project):

1. Set the "Attack"

• use a fast setting so the gate will open quickly for spoken words which tend to spike in volume suddenly (re-adjust later if needed)
  
  
• set around 0.4 ms (very fast)

 2. Set the "Release"

• use a somewhat slow setting, but not too slow, to create a natural, quick fading tail of sound between words and phrases (re-adjust later)
  
  
• around 415 ms (somewhat slow, but not too slow)

3. Lower the "Threshold"

• lower from 0 dB until you hear the spoken words clearly (though they'll sound a little choppy until attack, release and hold are dialed in to taste)
  
  
• around -33 dB (quite low to let quietest words come through)
  
  
• it's important to bring the "Threshold" down low enough so the "Attack" will open naturally for more softly spoken words as well as louder ones

4. Finally, adjust the "Attack" and "Release"

• get things sounding as natural and transparent as possible (where you can't really hear that the noise gate is working)
  
  
• add just a touch of "Hold" to let all spoken phrases through the gate

Do you want to grow in learning to convert problems in your dialogue voice recordings to simple corrections?

Maybe you just want a complete step by step guide to set up the noise gate above...

Grab my valuable, FREE resource to get started: Dialogue Audio Problem Solving Guide

Summary

Remember, using a noise gate to clean up background noise rather than a noise reduction tool, works best when your recording space is already optimized for clear and quiet recordings.

Next, if your recording space isn't ideal, using only a noise gate will give you results that probably won't be as clear sounding as using a noise reduction tool.

However, using the noise gate will usually be better sounding than nothing at all!

Finally, to effectively set up a free noise gate plug-in for background noise, use the "Attack", "Release" and "Threshold" settings.

Adjust these three to reduce noise while making the dialogue sound as natural as possible (where you can't really hear that the gate is working).

Have YOU tried one of these free noise gates for your dialogue voice recordings? How did it help?

What other plug-ins do you suggest for cleaning up background noise in your dialogue recordings?

Would love to hear your thoughts in a comment below!

Cheers, Bryan
Your Dialogue Editing Mentor