APU Software released APU Loudness Meter for free
The APU Loudness Meter plug-in is a free dynamic range analysis tool supporting a variety of loudness types (LUFS, True Peak, RMS, Peak). View changes to your audio’s loudness in real-time or get a bigger-picture look with configurable history and histogram views. View both real-time and accumulated statistical information all from one screen.
If you’re going to spend time using a loudness meter, it might as well be pleasant to look at. Real-time visuals are powered by hand-written OpenGL fragment shaders, providing beautiful iterative graphics which leave a trail of your audio’s loudness history in its wake.
More info and free download here: APU Software | Loudness Meter