PGRTA is pretty much the same thing as WMP bars display, just with less frequencies. The idea is to know there are tools to help 'see' what doesn't 'sound' right.
A lot of EQ's have this feature in various forms. (often called FFT)
Some do it as bars on the bands, some as linear.
I think Reaper EQ has this feature.
http://www.reaper.fm/reaplugs/index.php Most mastering softwares have it so you can make adjustments and see the result in the same window.
There used to be a few good spectrum analyzers out there for free, but they fell away with recent OS.
Voxengo Span is one you may still find.
Or Blue Cat
Or Audition has a nice one
Ozone4 has a very nice EQ interface for this
still a of few choices out there