On Thu Feb 01, 2007 at 07:46:39AM +0800, Chris McCormick wrote:

..if you want to do a ton of concurrent analysis, and have openGL acceleration
working, Tapestrea might be cool (ATI hates me too much for using linux to let
me try it)

if you dont mind the analysis being offline, check out sonic visualiser: http://www.sonicvisualiser.org/

CLAM might have one. see a full-color spectrogram in one of the screenshots, but
not in the patcher view: http://iua-share.upf.es/wikis/clam/images/8/83/NetEditQt4-PortMonitor-SpectralPeaks.png

in PD, just make a FFT transform of a signal block. this can be found in a
number of help patches..

you'll also want lots of controls to adjust the amplification, logarithmic
scaling, color palette, etc..

http://whats-your.name/i/licker.png is what i use , sure it uses more CPU than a
C implementation, but its more flexible, and you can plug it in anywhere in your
patch..