I figured this out, so I will answer my own question in case it comes up in somebody’s future search.
Kdenlive has the ability to affect entire tracks on its timeline with the same effect.
In my case, one audio track was voiceover narration recorded in a home studio, and the other audio was from the video that was captured in the wild. My process went like this:
- Make sure all narration is on the same audio track and all video sound on a separate one
- Drag the “Mute” effect onto each audio track
Disable “mute” effect on narration track
- Render entire project using “audio only” settings
- Re-enable “mute” on narration and mute the other track this time
- Render entire project to audio again
This results in 2 audio files that are both exactly the same duration as the project. You can then just stack them in the timeline and they will line up perfectly with the other tracks.
The reason to do this is so the audio mixing people can easily work on the separate tracks, and when they get the files back to me, I can easily plug them back into my project.