GNUsound stores its configuration information in a text file
in the location
~/.gnome/gnusound. Although some of the most
important properties that are stored in this file can be
edited from within GNUsound itself, this file also contains
other options that might be of interest. For example, it
contains the colors that GNUsound uses to draw various parts
of the interface. You can change these here if your aesthetic
sensibilities differ from those of the author. Some of the
more obscure options there may be documented in the
pref.c file.
It should be understood that editing the configuration file in this fashion may yield unexpected results. Also there is always a chance that the format of the file will change in the future, as well as the meaning of the properties and their values.
GNUsound saves all it's files as standard .WAV files. However not all of GNUsound's document settings can be preserved in the .WAV file format. Rather than inventing yet another sound file format, GNUsound saves the extra data alongside the sound file in a text file with the extension .USX. This file keeps track of the selection settings, markers, envelopes and mixer settings. This file is fairly self-explanatory and it doesn't hurt to edit it by hand.