If you are combining recordings or have multiple inputs into a recording it can be a real nightmare to get the levels right. Now you could spend a lot of time and money mixing in the different recordings, however a quick and easy method is to use Levelator.
It’s software that runs on Windows, OS X (universal binary), or Linux (Ubuntu) that adjusts the audio levels within your podcast or other audio file for variations from one speaker to the next, for example. It’s not a compressor, normalizer or limiter although it contains all three. It’s much more than those tools, and it’s much simpler to use. The UI is dirt-simple: Drag-and-drop any WAV or AIFF file onto The Leveler’s application window, and a few moments later you’ll find a new version which just sounds better.
Find out more about Levelator.