You can now save sound to a wave file from the sound options. You can choose to have a graphical monitor of what is being saved over the game screen.
This function is mixing the different sound channels to be saved in software mode. As a result, the sound might not be exactly like what you hear during gameplay. In some games, it might also be saved too loud (in this game you can hear distorsions). If it happens, just adjust sound volume with the mixer before starting to save to a wav file.
The wav file is named raine_sound.wav and is saved in the raine directory.