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In this course, professional audio engineer Scott Hirsch shows how to create an evocative sound mix for a film or video, built from basic audio collected during the shoot and transformed into a final mix using Pro Tools 9. This course shows how to set up and optimize a Pro Tools session template for projects with unique requirements, record Foley and ADR audio, layer sound effects, perform corrections such as noise reduction and pitch shifting, mix for stereo and 5.1 surround sound, and finally, how to format and deliver the finalized mix, whether destined for DVD, movie theater, broadcast, or the web.
In this movie we are going to go over some audio problems such as crackles or digital clicking. These can occur from lavalier mic radio interference or in the lavalier mic scratches against clothing, digital clock errors, or even when the audio overloads the preamp. Digital clicks from clock errors a lot of times may be seen in the waveform data in a Pro Tools track in a very zoomed in level. So here we have a piece of audio that does have a lot of digital clicks in it. Let's take a listen to it. (Woman speaking: In this example there are some digital clicks present. This can be due to a clock issue with a digital audio recording device.) Even from zoomed this far out you can see some digital clicks in this waveform.
Let me zoom in a lot more and we can really take a look at what these look like. See that spike right there? We have a pretty normal waveform and then a very violent spike right in the middle of it. So one of the ways we can deal with this in Pro Tools is actually to physically draw out each of these intermittent little spikes. It could be tedious but it does work. One of the things we should know before we draw out any of these waveforms is that this is one of the few operations in Pro Tools that actually destructively alters your original source audio file.
So to be safe what we want to do is make a copy of this file. The best way to do that is to double- click the region and we are going to go up into Edit and just say Consolidate Region. That's also Option+Shift or Alt+Shift+3. And it'll make a new region and we will name it whatever our track is named, in this case Audio 1, but in this case at least we will have a new whole file to be working on. Now there is two files, the old one on our hard drive and this new one. So we have the old one left behind. It has the clicks in it, but now we will be working on a different copy of the file.
So let me zoom in real close here and I am going to tackle this pretty obvious spike here. You can even make the waveform view a little bigger, zoom in there. Actually that went off the screen so I will zoom back. This seems like a pretty good view. So here I am going to use the Pencil tool. You can grab it up here or you can type F10 to change your cursor to the Pencil tool. The idea here is just to draw the waveform as if it would've normally gone without this spike. So it's going to start over here and draw it out something like that.
You have to be zoomed in to a pretty high level to get it to the point where you can draw the waveform. In other words you can't start drawing out here. You have to be this far zoomed in. Let's take a listen to that. I am going to just do a quick highlight over this section and we will hear it to see if the click is gone. (Inaudible) Okay, that's with the drawing I just did. Let's undo to hear the click and see if it's there. (Inaudible) So I definitely heard the click that time and I will redo that pencil draw. So it's real quick but we can tell that it got rid of that.
So now if I wanted to do this, I will have to go in and do a lot of redrawing, because there is a lot of clicks in here, but it is possible to deal with some of these noise issues with the Pencil tool at a very zoomed in level. Another way that we can deal with this also involves the iZotope suite of noise reduction, the Rx suite. Again, a standalone application. So what I am going to do is export this piece of audio. First let me name it, so it makes sense. I am going to call this crackle audio dupe since I duplicated it, so we are not working in the original whole file, and then I am going to Shift+Command+K or Shift+Ctrl+K on a PC and that gets it out of Pro Tools into this folder I made on the Desktop called NR for Noise Reduction.
Click Open and Export and I am going to tab over to my isotope application and from here we'll File > Open and let's open the crackle audio and it comes into isotope. Now double-click on the waveform here to select it all and isotope has a Declick & Decrackle function. So take it from over on the right-hand side and we will use the Declick tab. The Strength goes all the way up to 10, but that will give you the most artifacting.
So let's keep it down around 4 or 5 for this and we'll preview it and see if it's working. (Woman speaking: In this example there are some digital clicks present. This can be due to a clock issue with a digital audio recording device.) So as you can hear it's very effective and it told me that 135 clicks were repaired in that pass. So again this is without it. If I just hit Spacebar it'll play the original audio. (Woman speaking: In this example there are some digital clicks present.) And I'll preview it with. (Woman speaking: In this example there are some digital clicks present.) So that sounds pretty good.
I'll process it and the next step is to go File > Save As and I will just put a -NR, so this is my new noise reduced version, into the same folder, and what I do here is I go back to Pro Tools and from Pro Tools I can just simply go the Finder, find that NR folder and grab my noise reduced region, drag it right back into Pro Tools and I can line it up at this stage. So we'll hear the original one. (Woman speaking: In this example there are some digital clicks present.) And our noise reduced one.
(Woman speaking: In this example there are some digital clicks present.) You can hear it's not perfect but a lot of them are gone, so I might actually have to go back in and use the Pencil tool on some of these areas just to clean it up even further. So those are two methods to deal with crackles or clicks in audio and sometimes the combination of the two methods, the Rx and the Pencil tool, that might yield the best results.
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