A program that monitors
EsounD daemon and displays a graphical representation of
sound in various
gnarly and
funn-key ways (ie, basic
FFT and
oscilloscope displays, and the new version also has more detailed
spectrogram mode and such).
eXtace is part of GNOME, originally written by Rasterman - though I have to say eXtace isn't exactly GNOMEish in user interface. Well, intuitive nevertheless...