Join Maxim Jago for an in-depth discussion in this video Adaptive noise reduction, part of Audition CC Essential Training.
Adobe Audition is famous for its noise reduction technologies and some of them are incredible single click make it work options, and some of them are more complex. I'd like to start out now by showing you one of the really simple ways where you can turn on an effect and hope it will get better and it usually does. I'm going to browse down to this cleaning up audio directory. This is in our sessions listing and I'm going to open up, let me pull this out a little bit. Here we go, interview noise partially clean.
Lets double click to open this up and pull this over a little. Now in this version of my interview audio, I've already removed a background telephone ring and a really awful high pitch whine going on during the latter part of the interview. And this is an interview where someone is talking about a cyclist who their investing in his company. I'll just let you hear a little bit of it. >> Quo is an energy drink company committed to health and fitness. Johanna represents what (UNKNOWN) all about. When I first arrived I was. >> Okay, so it sounds pretty much okay, towards the beginning but in this later part we've got this very obvious hiss and its really visible if I pull up the special display, and just adjust my interface a little bit we can see this region that should be darkened isn't and all of this is background noise. Now there are a few ways of approaching this.
I'm going to show you a filter called Adaptive Noise Reduction. So, I can do this if I want to using the Effects Rack or I can do it using the Effects menu. And to begin with, I'm just going to pick my I-beam and I'm going to pick out just the section that has this very strong hiss in the background. I'm doing this, because I don't really mind about the early part of the audio, I think it sounds okay. What I really want to do is just deal with the background noise later on. And I want to start my preview at this point. I don't want to start previewing earlier back in the recording.
So I'm going to go to the Effects menu. I'm going to choose Noise Reduction. And I'm going to choose Adaptive Noise Reduction. Again, this is available on the Effects rack. Although, you'll notice that, it does not have the word process in brackets here to show that you're going to need to precalculate this effect. It does actually take up quite a bit of CPU processing power. In fact, if I click Close here, and choose this option here, here we go Adaptive Noise Reduction. Now I'm choosing this in the Effects rack, I'm getting a warning, and the warning is saying, well look, hold on.
If you don't have a reasonably powerful machine, you might find that you get some bad playback problems, if you're using this effect as part of a rack of other effects. You might be pushing a machine a little bit too hard. So just say okay there, close this panel. Just going to select this hit, delete, get rid of it. And let's go to our efrects menu and take it from there. It doesn't really make all that much difference in terms of the work that Audition does, but let's keep it simple. Now I'm just going to leave this on the default settings. I want to run over the controls with you, just a little bit.
But, to be honest, you'll find very often this effect works just find without you modifying anything. You will, of course, depending on your media, get better or worse results if you fiddle around with the options. First of all, let's just see how this sounds without changing a single option on the list. (SOUND) Now, do you notice how the noise is there at the beginning, but it fades away over the course of the playback. And that's the adaptive part of this noise reduction effect.
The idea is on the fly the system is going to identify frequencies or noise that should no the there and frequencies that should be there, separate them out and remove the unwanted parts. The result is actually pretty good in my experience, but you do have this problem where you need a lead up in advance. And in this example the lead up is not long enough, we've only got about a second there before the voice begins. And this is further reason why when you are recording location sound, if you're using Audition for post production audio, it's important that you get some additional background audio media.
Just so that your post production sound engineers has something to work with. You could always just have a run up at the beginning of unwanted sound and I suppose if you really wanted to go for it with this effect you could always copy and paste and paste and paste and introduce a lead up of that background sound to give the adaptive noise reduction effect something to work with. Now, just to skim over these controls. Most of these are pretty straight forward reduce noise by. Specifies in decibels how much you want unwanted parts of the audio to be reduced; in this case, we're setting it to 20 dB by default. There are some presets, of course, that adjust these a little bit, but the default usually works pretty well.
Noisiness is one of those slightly vague controls that defines the amount of the original audio that has noise in it. Again, you may just need to play with this to get better results. Then we've got the Noise Floor. Now the noise floor is the minimum level below which you want Audition to treat any sound as something that should be silenced, so just reduce anything below 2 db To zero DB. The signal threshold is the level above which Audition will presume that its hearing a sound a signal. Something you want to keep rather than background noise.
The spectral decay rate specifies how long Audition should hold any adjustments it has made before releasing them back to not making any adjustments to the audio at all. If you set this to long or too short, you can get some weird noises. So play with this to get the best results. And broadband preservation picks the frequency that Audition is going to remove, and then has kind of a window of upper and lower frequency around that that won't be affected. So 100 Hz means that for 100 Hz above or below the frequency that's removed will be safe.
So you've got about a 200 Hz window that's removed. Maximum and again you can adjust this if you want to. With all of these controls you'll find that extremes will tend to give you some pretty poor results. You need to experiment a little bit, if you want to adjust away from the default. The FFT size, the Fast Fourier Transform if you like, is the range of frequencies or the range of bands that are analyzed. In any given chunk. The analysis doesn't take place of the entire audio all at once. It's all broken into pieces. And higher or lower FFT sizes will give you variable results as well.
As you can tell from the way I'm describing this. This is an art and a craft to set up the effect as much as a technical set of specifications. And you can see a pretty obvious tick box here, High-Quality Mode, Slower, which just means that Audition will try harder and use more processing. If I tick this box and click Apply then click Away. You can see very, very clearly what's happened. It took a little while for the effect to identify the background noise. And then it does a pretty good job. Let's have listen. (SOUND) Not bad at all. Remember like any effect you work with in the Waveform view, this effect is destructive.
I have now modified my file and I need to save before those changes are applied. So, that's working with the Adaptive Noise Reduction effect in Adobe Audition.
Check out the new chapter, "2015 Creative Cloud New Features," for information on the latest features and enhancements in Audition CC.
- Introducing Adobe Audition
- Important audio terminology
- Importing and managing media files
- Working with sound files
- Making standard waveform audio adjustments
- Adding special effects to a file
- Cleaning up audio
- Multitrack editing
- Integration and output
Skill Level Beginner
Q: This course was updated on 06/19/2015. What changed?
A: We added one new chapter covering the 2015 enhancements to Audition CC.