
Martin Zuther (aka mzuther) has released traKmeter, a free (open source) loudness meter in VST plugin format for Windows and Linux.
traKmeter is a loudness meter for correctly setting up tracking and mixing levels.
traKmeter is available for free download on Martin Zuther’s website (2.3MB download size, 32-bit & 64-bit VST plugin format for Windows & Linux).
The plugin is designed as a utility for proper metering during the tracking and mixing stages. It features an average level meter (centered around -20dB RMS) and a peak level meter (aligned to -9dB), which should help you avoid any unwanted clipping while mixing.
Martin Zuther has recently released another great meter called K-Meter, which is basically a K-System meter designed according to specifications by Bob Katz.
There are no video demos for traKmeter available, however here’s a very informative video about the K-System:

Links
Download traKmeter: click here