How to Remove Background Noise from Voice Recordings Pt.5

We've gone in depth in the last 4 posts learning all about getting the best results from the spectral de-noise module to remove background noise.

That might be for your podcast, a sermon, voice-over for video or an audiobook recording.

Now let's apply all that knowledge and learn the exact step by step method for wiping out the noise in your dialogue voice recordings once and for all!

Setting Up and Using the De-noise Module

Let's get right into the step by step details when you need to remove background noise using RX's spectral de-noiser (*note: many of the principles here will work on any type of noise reduction plug-in).

1. First, open the spectral de-noiser and select the preset: "Highest Quality - Slow":

2. Next, make a selection of about 1/2 of a second or more of just background noise and click "Learn" (see noise selection below):

• you'll see the de-noise module create a noise profile from your selection
  
  
• iZotope RX's documentation recommends a few seconds for your selection, but I'm having success with just 1/2 of a second
  
  
• (read here on the best way to make background noise selections and why using just 1/2 of a second works)

3. Notice - your selection has to be ONLY consistent background noise:

• for example, when I tried to use a selection of noise and my breath, it didn't work
  
  
• instead of the frequencies of my breath being removed, frequencies of my spoken words were removed
  
  
• (read here on which noises to select and which to leave alone for the best results)
  
  
• see "bad noise profile" below where my breath (red arrow) was mistakenly included with the background noise
  
  
• in contrast see the "good noise profile" that is only background noise (further below):

[ Bad Noise Profile ]

[ Good Noise Profile ]

4. Now, select the "Output noise only" setting and hit "Preview" (see below):

• listen to a good chunk of your voice recording THROUGH the "Output noise only" setting
  
  
• this allows you to test if the de-noiser is reducing parts of your voice (which you don't want) along with the background noise
  
  
• if you hear something other than background noise (like parts of your spoken words), you need to go back to step 2 above and re-select ONLY background noise
  
  
• (read here for more on using the powerful "Output noise only" setting)

5. Next, unselect "Output noise only" and listen to a large portion of your recording through "Preview" (see below): 

• as you listen, switch back and forth using the "Bypass" setting
  
  
• it may help to loop your dialogue recording or a section of your recording for careful listening
  
  
• listen to hear if the noise reduction is removing background noise while preserving your words 

6. Continue listening back and forth with "Bypass" on for a few phrases, and then off:

• when "Bypass" is off, you should hear very little background noise at all
   
• if you still hear too much noise, bump the "Reduction" slider up to 13 or 14, but don't go overboard (see below)
  
  
• I've found that 12 dB is often a good balance of taking the noise down while not affecting the quality of my words too much

7. Continue listening back and forth with "Bypass" on for a few phrases, and then off:

• but CHANGE YOUR FOCUS to listening to the quality of the sound of your words with the noise reduction working
  
  
• do the words sound as clear and defined as they do when you "Bypass" the de-noiser?
  
  
• pro tip - your words will probably not sound exactly the same because the noise reduction process tends to reduce some high end frequencies as it gets rid of hiss
  
  
• no worries - but you ARE aiming for your dialogue to sound close to the unaffected words
  
  
• if not, try REDUCING the "Reduction" slider (move it down) to see if that helps
  
  
• but remember, it's going to be a compromise between reducing the noise and retaining the clear sound of your voice recording
  
  

8. Now, which sounds better - the "Bypassed" original recording with noise or the newly de-noised recording?

• remember our goal is to remove the background noise, so we'll accept a bit of high frequency loss
  
  
• if you've followed the preceding steps, you'll probably hear a MUCH IMPROVED dialogue recording
  
  
• it will sound much quieter and the words will be the main focus for your listeners, sounding clear and intelligible
  
  
• but, don't hit "Process" yet!
  
  

9. Finally, try this tip if you notice some high frequency loss when the spectral de-noise module is engaged (not in "Bypass"): 

• open the "Advanced settings" area 
  
  
• try boosting the "Synthesis" setting a bit more (see below) 

• it will be set at 7.0 already, but try boosting it to 7.5, 8.0 or 8.5
  
  
• listen carefully using "Preview" to hear if it helps bring back some high frequencies in your words
  
  
• this technique has helped in many of my voice recordings to retain a bit of clarity, life and air during noise reduction
  
  
• BUT, don't go overboard with this setting as you can introduce distortion in your voice
  
  
• listen back and forth again to find a good sounding setting
  
  
• you know you're in the right spot when a small boost helps the quality of your words sound closer to your unaffected words (when the de-noiser is "Bypassed")
  
  
• when you're satisfied with the sound, select "Process" (see below):

• pat yourself on the back - you're now a noise reduction pro and have learned how to dial in a quiet and clear dialogue voice recording with perspicacity!
  
  
• for an example of what your cleaned-up, de-noised audio might look like, see the "before" and "after" examples below:

[ BEFORE DE-NOISE ]

[ AFTER DE-NOISE ]

Summary

Remember, like most of the processing in RX and other audio repair software, your goal in removing background noise is transparency.

That is, you want to remove the noise in your dialogue voice recording without it noticeably affecting your spoken words.

Try to make your correcting and improvements "invisible" so to speak.

This will result in crisp and clear sounding dialogue with greatly reduced noise that your listeners will enjoy!

Have YOU used these steps on a recent dialogue recording? How did they help?

Would love to hear your thoughts in a comment below!

Cheers, Bryan
Your Dialogue Editing Mentor