Xtreme Media Player is a free cross-platform media player.
...A key feature of XtremeMP is the capability to view visualizations (on-screen graphics controlled by the music’s audio). These can have scientific/technical purposes such as depicting some properties of the audio (such as the Oscilloscope, Spectrum, Stereogram, and Spectrogram visualizations).
Luscinia is a program for archiving and analyzing field sound recordings (especially of animals). It incorporates an interface to a database, spectrogram measurement algorithms, sound comparison algorithms, and statistical analysis.