Soft Blue Waveform Remastering Tools

The light-blue area in Audacity waveform is the RMS amplitude, the dark-blue envelope is the peak amplitude.
If you normalize based on RMS, rather than on peak values,
the volume will be more consistent from one project to the next.

There is an Audacity plugin to “RMS normalize” here , (that plugin needs Audacity version 2.1.3 or later).