The Customize Fundamental Ranges Dialog lets you change the background of the Staff View, where the different ranges of normal singers and of overtone singers can be displayed.
You choose from several predefined profiles through the list box on the right:
This profile shows the normal four choir voice ranges Soprano, Alto, Tenor, and Bass.
This profile shows the four choir voice ranges, and the range of overtones that are singable in a controlled manner (by consciously amplifying specific overtones).
In this profile the singable overtones are divided by the technique used to produce them. The NG-Technique uses the entire oral cavity without the tongue and is more suitable for the lower overtones. The L Technique uses the tongue to divide the oral cavity into two separate chambers. This technique is used to produce the higher overtones.
The predefined frequency ranges are only approximations, and there are different opinions about what constitutes the range of singable overtones, and the choir voices. You can select the ranges that you want to display by changing the start and end frequencies for each voice.
This switch can be used to completely disable the display of the ranges when they are not needed, so that the Staff View will only show the music notes.
The Outer value specify the point where the voice starts to fade in from the background color, and the Inner value is the point where it will reach the full color.