Basic Audio Processing in Adobe Audition

A friend of mine recently edited his first TV commercial, and got this note from the TV station:

I wanted to let you know about the latest spots I just put in the system. The quality, especially of the audio, is quite bad.
The audio levels swing wildly from quiet to loud throughout, making the quieter parts hard to hear because I have to set the levels for the louder sections. Some of the audio also sounds like it was recorded a bit hot and distorts a bit. Also, some of the voiceover and stand ups audio only comes out of the left audio channel rather than both.

Ouch! Fortunately, aside from the audio that was recorded “a bit hot” and distorted, all of this can easily be fixed. Audio purists may be horrified by my approach, but it’s quick and effective.

The first step is to go through, and ensure that all your audio is playing through both channels. Do this by right-clicking on each dialogue clip, selecting “Audio Channels” from the pop-up menu, and then switching both tracks to whichever channel has the audio. In this screenshot, you see what it looks like to switch both Channel 1 and Channel 2 to use the Left channel audio.
set-channels-to-left

You can also use the “Fill Left” and “Fill Right” filters to accomplish the same end. It’s a matter of personal preference.

Next, mute all the background sound effects and/or music, and export just the dialogue from the sequence in Premiere as a high-quality AIFF file. If you check the “Import into project” checkbox, Premiere will suck the new file right back in for you, which is helpful.
export-AIFF-from-premiere

Then, put the complete file into your sequence, mute all the dialogue tracks (you’re now replacing them with this compilation file), right-click on the compilation audio track, and select “Edit clip in Adobe Audition” from the pop-up menu. Adobe Audition will automatically open, and you’ll see the waveform of your file.
audio-process-1

The first step is to squash down all the audio that’s way hotter than the average. Do that by double-clicking on the waveform to select the entire thing, and then clicking on Effects -> Dynamics and Compression -> Hard Limiter.
audio-process-2---hard-limiter

You don’t want to crush the audio unnecessarily, but you do need to push the peaks close to the valleys. Start by limiting it to -20 and then adjust as necessary.
audio-process-2b---hard-limiter-settings

Now, everything is close in amplitude, but it’s all too quiet. To fix that, use Effects -> Dynamics and Compression -> Normalize.
audio-process-3---normalize

Go ahead and tell Normalize to pull everything up to 0db. You can always turn it down later, if necessary.
audio-process-3b---normalize-settings

If you hear a buzzing in the background of your audio, it’s probably a 60khz hum from an electrical appliance. Use Effects -> Noise Reduction -> DeHummer to fix it.
audio-process-4---dehummer

DeHummer tends to be a bit aggressive. The -60 setting tends to degrade the dialogue, in my opinion. Try -40 and see how it sounds to you.
audio-process-4b---dehummer-settings

When you’re finished, click File -> Save, and then switch back to Premiere. Your original track will automatically be updated. Unmute your sound effects and/or music, and listen to how everything sounds together. Keep an eye on the audio meters; you want the levels to be jumping around the -6 area. If they’re too loud, apply the Volume filter to your processed audio file, and turn it down until it’s within the desirable range.
audio-process-5---processed

There’s a lot more to this: using “rubber-band” editing in Premiere, and noise reduction in Adobe Audition are good skills to have as well, but when you’re under the gun, this is a quick and easy way to get your audio into the right ballpark.

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