OS X 10.10.2; Audacity 2.1.2 obtained via .dmg installer.
I download and listen to approx 20 separate and distinct .mp3 speech (not music) files daily. I listen to them with a mp3 player at work, in a noisy manufacturing environment. The quality of some of the files is acceptable. Others have portions that are way too quiet, but then have small, very loud portions, such as loud bumper music, or one soft spoken person with another being very loud.
Unfortunately, I don’t have the time to examine each one, so they need to be done in a batch (chain?). Also, I don’t know to decide whether to use, for instance, the Leveler, or Limiter, or Amplifier, or Compressor, or Normalizer; or in what combination or order.
Some only need to be leveled. Some only need to be amplified. Some need to be both leveled and amplified. And it would be nice if they were all normalized (but this part isn’t required).
The distortions, say, from clipping aren’t really important. The important part is being able to hear and understand the speech.
Then I need to export the results into an 96 kbps .mp3 file.
What is the best way to construct the chain so that it will fix the problematic .mp3 files without seriously degrading the good .mp3 files?