NLE Tips – Audio Track Mixing in Final Cut Pro

In the past I’ve explained how audio in routed through the Final Cut Pro architecture. I’ve also discussed track-based audio mixing, predominantly based on the workflow in Premiere Pro. Today I’d like to extend that workflow into the realm of Final Cut Pro.

Everyone knows that FCP is not track-based. The timeline consists of a string of audio/video clips called the primary storyline, which empowers its magnetic feature. Additional audio and video clips can be attached to the clips on the primary storyline as connected clips – video above, audio below. At this level the software is indeed trackless. (Click on any image to see an enlarged view.)

Understanding audio roles and lanes

Several years ago, Apple added the “roles” feature. Audio and video clips can be assigned default and/or custom role designations, which can be used for visual organization and other functions. For example, do you want to export a “textless” ProRes file from your timeline? Then simply disable the Titles video role in the export dialogue.

Apple engineers have done more with audio roles, which can be further grouped into audio “lanes” through the timeline index window. If you’ve assigned the correct audio roles to each clip, then all dialogue clips are grouped into the dialogue lane, all music clips in the music lane, and so on. If you exported an FCPXML file for an outside mixer, then audio roles help to organize the track layout in other audio software.

At this point the clips are still individual. However, once you combine all clips in the sequence into a single compound clip, then the audio for all clips within an audio lane are summed together. This is similar to a group or submix bus in a DAW. The combination of lanes are in turn summed together and sent to the mix output. In essence, each audio lane within the compound clip is similar to a summing track stack in Logic Pro. You can adjust volume and apply effects to the entire lane, on top of anything done to individual clips contained inside of that lane.

Mixing in FCP on real-world projects

I’m working on an Alaska travelogue series – on-camera host on location, voice-overs, voice-over pick-ups, and music. The host stand-ups were recorded in two environments – close to the shoreline and in a quiet wooded area.

The location sound mixer recorded both a Lavaliere mic and a boom mic on separate channels. My personal preference is the boom, but sometimes the waves on the beach created too much background noise. In those cases, it’s the lav mic, but then I have to contend with the duller sound of the mic under the clothing, along with some rustle.

The next challenge is getting the voice-overs to sound close to the on-camera audio. These were recorded on location, but in a quiet room. The final challenge is to match the sonic quality of the voice-over pick-ups (done by the host at his home) to the original voice-overs.

Step One

The first step in this process is to assign the proper audio roles before clips are edited into the FCP sequence. Roles are quite versatile. If you had multiple speakers, each one could be assigned a separate role. In this project, my audio roles are Dialogue, VO, VO2, and Music. Once clips are imported and roles assigned, I can edit as I normally would in Final Cut. I personally add very few audio effects at this point to the individual clips, because I will do that later. In addition, certain effects, like noise reduction simply don’t work very well with short clips (more on that in a minute). So I only add what I need to “sell” the cut.

Step Two

Once the cut is approved and locked, I can move on to a final mix. To start, I’ll remove any audio effects that I’ve added to individual clips. Then, I meticulously go through and even out any level imbalances. Final Cut Pro features multiple gain stages. You have the clip volume control, but if you expand the audio, you see the individual channels, which each have volume controls, as well. Each of these can be raised by up to 12dB. So if you’ve applied 12dB to the clip and it’s still too quiet, expand the audio and bump up the channel volume. Or work this process in reverse. My objective is to end up with a clip volume that’s a bit hot in the peaks and then use the range tool to highlight the larger peaks and duck them down a bit.

Expand audio and make sure you have overlaps with fade handles between all clips. This is somewhat time-consuming. It’s far simpler in Premiere Pro to add audio dissolves (crossfades) across all audio edits in the timeline in a single step. But it’s a necessary step, including the addition or room tone/ambience to fill any gaps in the speech.

Finally, check the music. Make sure the edits work musically. Overall, the music volume can be a bit loud at this stage, but you want to make sure the balance is right for the entire sequence. So pay attention to the proper and graceful ducking of music around spoken audio.

Step Three

After you’ve made everything as uniform as possible, compound the sequence. Open the timeline index, enable “show audio lanes” which expands the audio of the compound. You’ll now see a “track” or summing bus for each audio role – Dialogue, VO, VO2, and Music. When you select an audio lane, you can adjust its volume and apply audio effects to only that lane. That lane’s audio parameters are shown in the inspector pane.

Selecting the topmost level of the clip, displays the output (i..e mix) bus parameters. Additional effects can be added here. It’s fine to apply and adjust such “master” effects, but I recommend that you do not make any changes to the volume. That’s because the volume control comes after any effects, which would include a meter plug-in, such as the built-in multimeter plug-in. Leave the volume slider alone if you want to see accurate volume levels.

Aside from mixing in tracks/busses, audio roles add another value at the time of export. My deliverables include a ProRes file without titles, as well as audio that’s split into separate tracks. In Final Cut Pro’s export setting, I can select the Multitrack Quicktime and then arrange the combination and order of roles. For this project, it’s a ProRes file with four stereo tracks corresponding to the four roles that I’m working with.

Note that when you export a multitrack file, each lane output also has any master output effects added to them. For example, if your mix uses a compressor and a limiter on the main output of the compound clip, then each lane/bus/track of the multitrack will now also have the added effect of that compression and limiting. If you don’t want this, then make sure to disable these effects prior to exporting a Multitrack Quicktime file.

Which effects should you use?

I’ve now discussed how the process works, but what combination of effects should you be using? Obviously that’s a question of style and personal taste. The type of effects for me will be similar to my description in the Premiere Pro article. I tend to stick with native Final Cut Pro effects, so that I don’t have to worry about what’s installed if I move to another Mac or a different editor has to step in. Also, Final Cut Pro is often a poor host for some third party audio plug-ins. I don’t know the reason, but have been told it’s up to those developers to optimize their tools for FCP. In most cases these same plug-ins work well in Logic Pro, not to mention other non-Apple applications. Go figure!

I’m happy with most of the built-in Apple audio plug-ins, with the exception of noise reduction and other audio repair tasks. The Accusonus tools are my go-to, but they are sadly no longer available. After that it’s the RX package from iZotope. If you have a really challenging piece of audio, then use the standalone RX package on that clip and re-import. If you don’t own either of these, then the newly added voice isolation feature in Resolve is pretty sweet (and better than what’s in FCP). Another impressive contender is Adobe’s Podcast beta. The AI-powered voice enhancement feature is available for free use through their web portal. I’ve used it for some really poor Zoom interview audio and it did an outstanding job of cleaning up all manner of audio defects.

Where this explanation is most pertinent is on location-based dialogue recordings. These are the ones that often benefit from noise removal/repair. These tools require consistency and some lead-in to the first audio, so they are best applied to full tracks and not individual clips. That’s why I make sure I have overlaps and fill in gaps and do all of this processing on the lanes of the compound and not on individual clips. If you have different dialogue sections – some noisy and some clean – then it’s best to organize these into separate audio roles, so that they are sorted out correctly once you compound the clip.

My typical processing chain

My FCP effects layout is similar to the description in the Premiere Pro post. Dialogue and VO tracks get some noise reduction, EQ, and compression. Voice-overs are particularly susceptible to plosives (popping “p” consonants) and sibilance, so plosive and de-essing filters are useful. For music, I usually spread the stereo image more and dip the EQ in the midrange. Plus some compression. All of this is designed to allow the dialogue to sit better in the mix. 

The last level of processing is what you do to the top level of the compound clip itself. That’s a bit like mastering in audio production. Applying effects to the compound clips is analogous to applying effects to a mix or output bus in the DAW world. On this particular chain, it’s EQ, exciter, compressor, adaptive limiter, and the multimeter. The effects stack is processed before the volume slider. Since I’m judging peak and loudness levels with the multimeter plug-in, I don’t want to make any volume slider changes on the compound clip, because those would be applied after the reading on the multimeter.

You’ll notice from my screen grabs that different compressor models have been used. These are all from the same Logic Pro compressor in FCP. This single plug-in features various presets designed to emulate tried-and-true analog compressors favored by top recording engineers/mixers.

Final thoughts 

As with my other Final Cut Pro audio articles and posts, I can already hear some screaming that this is just a workaround for the fact that Final Cut Pro has no “true” audio mixing panel. While that may be true, it’s also irrelevant. Until such time as Apple’s ProApps engineers redesign the audio section or add a “roles-based mixer” to the tool set, this is the software you have. If you want to mix in Final Cut Pro and deliver a properly mixed master file without using specialized audio software, then it’s best to understand how to achieve the required results.

If you step into the compound clip to make any editorial changes to the sequence or to individual clips, then you will not hear the results of the top-level mixing and effects. The proper mix is only heard when you step back out. This is a short-coming compared with this same process in Premiere Pro. Therefore, when you are editing in Final Cut Pro, it’s best to leave all of the final mixing until the end. In Premiere Pro, I tend to mix as I go.

Hopefully this post gives you some insight into the “guts” of the software. If you can’t send the audio to a mix engineer and don’t want to bounce over to Logic Pro, Pro Tools, or Resolve (Fairlight) yourself, then there’s no reason Final Cut Pro can’t be made to work for you.

©2023 Oliver Peters