FFMPEG Audio Volume Command

I’m still driving myself crazy trying to test & correct audio volume problems on AVI files. I have a number of videos (using MP3 audio) with either too low or too high an audio volume and I’m looking to normalize them.

Is there a command line for FFMPEG or some other program to compare a file to a Target ‘Normal’ of 89 DB? I would like it to give an indication of how many DB’s are necessary to bring it up or down to 89.

Thanks in advance,
John