Hi Bruce…
Track level automation done by either the pen tool or the mixer, the result is the same. Keyframes on the track.
However, there is an important distinction between clip keyframes and track keyframes.
If you set your audio tracks to clip mode, and add key frames to the clips, then ripple edits and rearrangements will respect those keyframes and move with the clips. These keyframes can only be set with the pen tool in the timeline or in the effects controls panel for the individual clips
If you set your tracks to track mode (which you were in) when you add keyframes, they are not associated with individual clips, but rather just a absolute position in time on a track and thus don’t move when you, ripple the events on the timeline.
The same is true for audio effects (like reverb). they can be inserted and automated on clips or in the mixer bus at the track level. Effects and their automation applied at the clip level will follow the clip as you move/trim it.
Why would you want to do this?
It’s global versus local.
Let say you get your cut in line and you want to start EQing, adjusting dynamics and wetness a particular talking head that you cut back to throughout a edit.
If, after you edit, you isolate all the audio from that talking head down onto a particular track (a logical grouping if you will). Then you can apply the effects in the mixer and it will apply consistently to all clips on that track. Thus if you need to make changes, you make adjustments in one place. This is also important for wet/environmental effects, where, because the effects processing happens at the track level, reverbs will have natural decay, even if the edit event ends. If you apply reverbs at the clip level, the reverb will cut abruptly at the end of the edited event on the timeline.
For levels editing, applying local keyframes at the clip level can help you smooth out jarring inconsistencies of peaks and valleys, but then you can make those now smoothed clips fit into the overall mix by adjusting at the mixer level.
For music beds there may be specific passages that you want to control the level of. That may be better approached at the clip level. But if you are formatting a mix for a TV breaks in a show, you can add some automation at the track level. If the breaks need to happen at specified intervals, then you can replace the music clip, but the automation taking you in and out of a commercial break will still be in place.
Hope this gives you some ideas as to how to approach audio in PPro.
Alex Udell
Editing, Motion Graphics, and Visual FX