I don't know if you got your answer, but Levalator is a stand alone application. You load your audio file into it, then it reduces the gain, volume, of the loud sections and also raises the volume of the soft sections.

Therefore for music it does present some drawbacks and it reduces the overall dynamic range of the music, soft versus loud portions.

I used it recently to level out some speaker presentations for training videos I was creating and it worked great for that application of the software.

Good luck