This area shows the wave form of sound, and what part of the sound is currently selected (Selected area).
The sound wave form is yellow and the background color is cyan or navy blue. When an area is selected, the background color is cyan. When it isn't, the color is navy blue.
The operator can set selected area. The procedure is shown in Advanced modification.
The horizontal scale is time. Its short pitch is 0.055 seconds. The vertical scale is intensity of power. Its short pitch is 20% of maximum wave intensity of this format.