If I want to reduce the volume for a section of a track, I can always use audio effects/gain change for that particular section. That's fine, but this changes the audio file permanently, and cannot be undone after saving (unless by loading the project from a backup, of course).
Its seems that we can control this with "envelopes" in piano roll view. As this won't change the audio file, it seems like the better alternative. But for a newbie its difficult to see how this should be done with the "drawing" tool at the bottom of the piano roll window. And the manual isn't very helpful, to be honest.
So please assist a newbie here: Am I right in preferring the envelope alternative to permanent audio effects, and - if so - how do I use this tool? Any help much appreciated.