1. Click the toggle on the Sound Grapher display as shown below to see the controls.

2. Click the FFT check box to turn on the frequency grapher.
3. Click the OK button to close the controls view.

Once the frequency grapher has been turned on, you will see a different display for the Sound Grapher. In the example below, the top window shows the sound wave as usual, but the bottom window shows the frequencies of the sound.