Un ottimo software per l’analisi del suono e per di più open source e gratuito sviluppato presso il Centre for Digital Music at Queen Mary, University of London.
Prodotto per Linux e Windoze (io ho provato solo il primo, ma suppongo siano uguali), dispone, fra l’altro, di FFT, spettrogramma 2D, stima del pitch e possibilità di inserire annotazioni in overlay. Su Linux è in grado di utilizzare tutti i LADSPA plugins per l’elaborazione audio. Ottimo per il ricercatore e per il musicista elettronico. Cliccate sull’immagine per ingrandirla.
Ecco il sito da cui scaricarlo e la pagina delle features.

The aim of Sonic Visualiser is to be the first program you reach for when want to study a musical recording rather than simply listen to it.
As well as a number of features designed to make exploring audio data as revealing and fun as possible, Sonic Visualiser also has powerful annotation capabilities to help you to describe what you find, and the ability to run automated annotation and analysis plugins in the Vamp analysis plugin format – as well as applying standard audio effects.
We hope Sonic Visualiser will be of particular interest to musicologists, archivists, signal-processing researchers and anyone else looking for a friendly way to take a look at what lies inside the audio file.
Sonic Visualiser is Free Software, distributed under the GNU General Public License and available for Linux, OS/X, and Windows. It was developed at the Centre for Digital Music at Queen Mary, University of London, by Chris Cannam (of Fervent Software, Rosegarden, Studio to Go!, and DSSI).

Here is the site and the features page.