To get started with your USB audio interface, just plug it into a USB port. Plugging in and finding your new USB audio interface The familar volume menu item lets you select an output device for audio. In between there’s a huge range of options, from USB headphone amps costing many thousands of dollars, and meant for just one pair of headphones, to budget mixers that let musicians record great quality audio at home on modest budgets. At the other end of the list is something like a mixing console, which will have many inputs, allowing your to hook up, say, 16 different inputs and have them all piped into your GarageBand app. These are popular with podcasters, for example. The simplest USB audio device is a USB microphone, which can be plugged direct into your computer and used to record.
