Using Cool Edit, I used to be able to do all of the following. Can’t do any with Audacity.
Determine the average volume/loudness of a selection. I can view the spectrum, but not the volume.
Vary the amplitude of a selection over its width. (I think it’s call an envelope function.) Example: allow a boost of, say, 3 dB at the left end of the selection and a boost of 1 dB at the right end, with the gain varying linearly (or by some other user-selected contour) between the end points. This would allow me to even out the volume of a song that starts softly during the into, then slowly builds up to the main volume. (I know there is a Normalize function; it doesn’t do this. I may still want some variation during the selection; Normalize doesn’t give me that fine control.)
Delete a middle portion of a song to shorten its length, while maintaining continuity of the main beat. With Cool Edit, I would play the song and tap out a marker for every main beat leading up to the section to be deleted. Then I would do the same as I approached the end of the section to be deleted. After making sure the key beginning and end markers were accurately placed on the beats, and repositioning them as needed, I would just make a selection between the two markers and delete it.
But does the labels go exactly on the kick drum, or the like? Then the cut happens at place with loudest volume. That is just bad.
OK. First select between the labels. Then, can the selection be moved so that the ends lands between the kick drums? The length remains the same.
Beat detection? Automatic placement of the labels?
Selection quantization? So that no labels are needed. A grid, and the selection snaps to nearest grid point. Quantization by BPM value.
Example. I have loops for a song if I want make a remix. I examined the original song by splitting the whole song to pieces. This is not a trivial split, but if I would place the splits to Audacity, the splits would fill multiple tracks and would overlap. It is like figuring out the original arrangement without access to the original cues.