The Focusrite Forte is one of the best compact desktop-style USB audio interfaces on the market. One of the great things about it (aside from its standard-setting audio quality) is that the user interface is so simple — just a single large knob that also doubles as a switch when you push it.
But just because you only have one knob doesn’t mean that you are limited in what you can control. Simply push and hold the control knob. When you do, the OLED screen will change to display different parameters, depending on whether you are looking in input, line output, headphone output, or DAW control modes. (The mode is selected by pressing the icons under the Forte’s screen.)