Cut Lines: Working With Sound in Final Cut Pro
Posted Mar 5, 2009

Someone recently asked me about managing soundtracks in Final Cut Pro (FCP), and I realized this is a subject of great interest in my classes also. This month, I'll focus on the various ways to manage soundtracks and
sound-mixing tools in FCP 6. From capture to mixing, this article will give you the basic tools for managing how you work with soundtracks efficiently and easily.

Set Audio Tracks to Capture
In FCP, when you capture, you can set the audio tracks to capture. If you want only one channel, you can disable the other; the QuickTime (QT) clip that FCP makes will have only one mono audio track. In Log & Capture, select the Clip Settings tab and open the Audio section. Locate the symbol that looks like an infinity sign (two speaker cones side by side) on the left; it’s between the audio channel controls, which is colored gray. Click it to link and unlink the two audio tracks (Figure 1, below).

When the tracks are linked, the link lines appear, and you can record a stereo pair. This is the default. The audio shows up in the Viewer as only one tab, and any filters, keyframes, or adjustments to pan/volume that you apply will affect both channels together at the same time. They are married to each other. When the tracks are unlinked, you can record a clip with two independent mono tracks, each with its own tab when it’s opened in the Viewer.

You can put in filters and keyframes and adjust pan/volume independently on each. The next thing to address is the green buttons next to each track. When the tracks are linked, both of them are recorded, period. When they are unlinked, you can enable or disable each or both tracks to be captured. Let’s say you recorded an interview on Ch1, and Ch2 is just ambient camera-mic noise. Unlink the audio channels and then click Ch2 to disable it. Then, when you capture, you’ll have a video clip with Ch1 as a single mono track. Ch2 is totally ignored and is forfeited during capture.

Final Cut Pro's Audio Clip Settings tab

Adjust Settings After Capture
After capture, you’re not locked into the choices you made during the capture process. If you capture the clip as a stereo pair and open the clip in the Viewer, you’ll see one audio tab that has two tracks, married to each other. If you drop that same clip into the Timeline and double-click it to open that Timeline copy back into the Viewer, you’ll see the same thing. But if you highlight that clip in the Timeline while the Timeline window is the active window, go to the Modify menu to Stereo Pair and click it to uncheck that option. Then, open that clip into the Viewer, and presto! You’ll have two mono tracks (Figure 2, below).

Uncheckl Stereo Pair to get 2 mono tracks

If you Unlink the clip in the Timeline (Modify > Link or Cmd+L), you can then select each audio track separately and delete the one you don’t want. The trick is that the pan on that track will still be to one side or the other. You’ll have to change the Pan to 0. If you captured the clips as two mono tracks, once you’re working in the timeline and using the same menu command, you can make two mono tracks a stereo pair as well.

Use Waveform Overlays
Another very useful tool for working with sound in the timeline involves the audio waveform overlays. This can be very handy for getting edit points lined up precisely with specific events in a sound track. With the Timeline window active, use the Cmd+Opt+w keyboard shortcut to toggle the audio waveform overlays on and off (Figure 3, below).

Audio waveform displays in the FCP timeline

You will now see sound waveforms over the sound clips. If you zoom in close enough, you’ll find plenty of detail to help you make the most precise sync-to-sound editing easier. You can also find it in the Timeline Layout Popup menu, located at the bottom left of the Timeline window.

Work in the Viewer Window Pan Control
Next, here’s a note about the Pan control with a stereo pair (which applies only to clips with a stereo pair element to them). A Pan setting of -1 sends the right channel of the audio to the right channel of the playback. A Pan setting of 0 sends both channels to both outputs. Right goes both left and right, and Left goes both left and right in a mono playback scheme. A Pan setting of +1 sends the right channel of the audio to the left channel of playback and the left channel of audio to the right channel of playback. Moving the slider is basically pulling Ch1 and Ch2 from their native side to the center and then to the opposite side, if you follow me.

Here’s how I explain it in my classes: Pretend you’re holding a small audio speaker in each hand, with the right channel in your right hand and the left channel in your left hand, pointing the speakers in front of you while you’re playing a stereo recording. You hold the speakers with your right hand out to your right and your left hand out to your left. This is a -1 pan. Why -1? Good question—let me know when you figure it out. I just accept that’s how audio works. There’s some engineering reason for it, but we won’t go there right now.

If you pull your hands—while still holding the speakers—to right in front of your face, placing one hand above the other and just dead center in front of your face, this is a 0 Pan. In this scenario, the two speakers behave like two mono channels. You just pulled the slider in FCP from -1 to 0 by doing this.

Now, move your right hand and the speaker over past your left shoulder. And move your left hand and the speaker over past your right shoulder, crossing your arms. This is a +1 Pan. Each speaker is now on the opposite side it’s supposed to be. You just moved the FCP slider from 0 to +1.

Now, move your hands back out to your sides, in your starting position. Move your right hand and the speaker to your right. Move your left hand and the speaker to your left. You just moved the FCP slider from +1 to -1 (Figure 4, below). That should make the FCP Pan controller very clear now.

Changing values in Final Cut Pro's Pan controller

The other thing about sound in the Viewer window is that you can zoom in and out of it, just as in the Canvas and Timeline windows. The command key used with the plus and minus sign keys (the ones at the top right of your keyboard to the left of the delete key) will zoom you in and out of the audio clip. This can be very useful when you are setting precise In and Out points.

Use the Sound Mixer Tool
When you’re ready to mix the overall sound in FCP, go to Window > Arrange > Audio Mixing. This menu will give you the audio mixing window layout that helps a great deal. You can mix sound in real time, either in practice mode or in keyframe mode. Notice the Audio Mixer in the Tool Bench window (Figure 5, below). This is where the magic happens. And it’s pretty flexible. Here’s how it works.

The Audio Mixer in Final Cut Pro's Tool Bench window

Across the top of the window, you’ll see the “View:” buttons. These let you customize four different views of your audio tracks. For example, let’s say I have voice-over work on audio tracks 1 and 2. I have sound effects for my cutaway shots on tracks 3 and 4. I have music on tracks 5 and 6. That’s six tracks to keep up with during the mix! When I click on View button 1, I see all six tracks. If I click on View button 2, then on the left side of the Audio Mixer window I’ll see a column of Tracks: A1, A2, A3, A4, A5, and A6. Each has a button, or dot, to the left of it. I can click on those buttons to make each track appear or not inside that specific View. All the tracks will still play; I’m controlling only what I “see” in that View.

So if I click on View button 2, I’ll only let tracks 1 and 2 (voice-over) appear. If I click on button 3, I get only tracks 3 and 4 (cutaway sounds). Button 4 gives me only tracks 5 and 6 (music). In this way I can concentrate on only one set of tracks at a time without being distracted by the other 4 tracks while I’m doing precise mixing.

What’s more, in each track I can see in a given View, by clicking the headphone icon to solo (i.e., hear by itself) only a specific track, pan slider, volume slider, and level meter. I can also click one of the speaker buttons to mute a track. I also have a Master level and slider. All sliders have numerical fields for more detailed feedback. You can also click inside these fields to type in numerical values.
Now, look up at the top right of the Audio Mixer window. You’ll see a button that has the icon of a little audio speaker with a keyframe diamond next to it. When that diamond is gray, keyframing is turned off; when it’s green, keyframing is turned on. As you might guess, I can adjust my sliders with keyframing turned off as a sort of practice mode. I’ll play my Sequence several times, practicing and getting a good feel for how to mix it properly. And I can jump between my various views. I can solo my voice-over and get its level optimally set.

Then, with only my voice-over and cutaway sounds enabled, I can go to View 3 and concentrate on those sounds. Then, I can enable all my soundtracks and, in View 4, mix my sound, raising it slightly in between voice-over pieces, lowering it slightly during the narration. It’s all pretty easy to figure out and use.

When I’ve practiced enough and I’m sure I know where to set various levels on various tracks, I’ll click the Audio Keyframes button to make it green. Now, when I mix live during playback, audio keyframes will appear, applying my use of the Audio Mixer to the actual sound clips. All in all, it’s pretty easy. But there are a couple more things you need to understand to use it most effectively.

Whatever clip the playhead is positioned over on a given track is the playhead the mixer is affecting at that moment. If your playhead is playing over a section of a track that has no audio clips, the level slider for that track will jump to the lowest setting (negative-infinity), and you will not be able to move them. As soon as the playhead hits another sound clip in that track, they become active again for that track.

Record Audio Keyframes
The other thing to note is the audio keyframe setting in the User Preferences. If you go to the Final Cut Pro menu > User Preferences and select the Editing tab, in the right column you’ll see the Record Audio Keyframes option (Figure 6, below). Checking or unchecking the box next to it is the same as clicking the button to turn the function on and off in the mixer window. The pop-up menu here gives you three choices: All, Reduced, or Peaks Only. This controls how many keyframes are placed when you’re recording your live mix.

The Record Audio Keyframes option in Final Cut Pro User Prefs

“All” records a great number of keyframes and is normally only used for really precise, very detailed mixing. I recommend against using it because the more keyframes you have in your sequence, the more resources you’re making FCP demand from your computer system. And it makes so many, it simply gets confusing. “Reduced” is what you’ll normally use. It places fewer keyframes but still enough to let you have a good bit of smooth control over your live audio mix. “Peaks Only” are just what they sound like: A keyframe is marked where the level slider reaches the highest or lowest point (i.e., peaks) when you let go of it. This option leaves a bare minimum of keyframes, and, although I occasionally find it useful, I suspect it’s not something you’ll normally want to fool with.

The cool thing about these keyframes is that you can open each sound clip into the Viewer window to actually tweak the keyframes, moving them up, down, left, and right to get the mix more precise. You can tweak these keyframes inside the Timeline as well.

Opt+W turns on and off the Clip Overlays, showing you, in audio clips, a red line. This line is the sound level of your clips. If you zoom in to your timeline window enough, you can actually grab the keyframes right there, even with the waveform overlays turned on, to make more precise adjustments to your mix. Right-click on a keyframe and you can clear it. Press P to switch to the Pen tool in the Timeline window and click on that red line to create new keyframes. Press A to switch back to the normal arrow, or click the Selection tool to move the keyframes around.

So there it is; pretty much all you need to start working with sound in Final Cut Pro. Once you start to take a good look at these tools, I’m sure you’ll figure out what each function does pretty easily. Until next time, happy editing!

Ben Balser (benb at is an Apple Certified Trainer based in New Orleans. Along with training and consulting, he also produces documentaries and educational material, and he designs digital signage systems.