Digital Sound Enhancement?

you have an option on mmjb to apply volume leveling (for when you have inconsistant mp3's that are LOUD and others that are soft, you can have mmjb tone down the loud ones) to your mp3's. "apply current digital sound enhancement" will bring over those changes to the ipod. Other programs probably have other different "digital sound enhancements" that it can make to your mp3s as well.