Human Auditory System: Apple patent application for hearing protection

The iPodObserver, among others, is reporting on an Apple (US consumer electronics and computer company) patent application on a way to automatically protect a listener's hearing based not only on a maximum level constraint but also adding the total listening time variable.  To put it another way, the longer one listens to elevated sound levels, the quieter they need to be as the time progresses to avoid hearing damage.  I haven't read the patent application yet, so I am uncertain as to exactly what the novel aspect of the invention is, but taken by itself, I see it as a good move an industry leader to make their product safer.