Virtually all types of "filter" have some delay before they get going properly, and the Noise Removal effect is no different. As you can see in the second image, this produces a very brief "fade in" type effect during the first 1 ms or so of the selection. As long as the track starts at zero amplitude (which is often the case, then there would normally be no "click" caused by this. The problem that you are probably experiencing is that the track splits do not occur at places where the amplitude is zero, so when you process the tracks (individually), there is a resulting mismatch between the end of one track and the start of the next.
What you could perhaps do is to import all tracks from one side of the album and position them end-to-end on the same Audacity track (use the
Time Shift tool). Then select the entire Audacity track and apply Noise Removal to that.
The track may be re-split into separate tracks by using "Export Multiple" as described here:
http://manual.audacityteam.org/o/man/sp ... racks.html
Tip:
The quickest way to add a label to an audio clip (you will have separate audio clips in one audio track - one clip for each song), is to double click on the audio clip (selects the audio clip), then press
Ctrl+B You can also add text to the label if you wish, which can then be used as the track names when you Export Multiple (Press "Enter" to close the label).
This forum is for Audacity on Windows.
