As the name suggests, the Mackie Big Knob is an audio control center with, well, a big knob. But it offers a lot more than that: studio monitor selection, input source selection, talkback and headphone control, and more. The Big Knob includes four stereo inputs, as well as a phono preamp for your turntable and two headphone inputs. It's even got 8 input channels and 16 output channels!