Digital Audio Dialog Options: Direct Support Use the Direct Support popup to select the audio device you wish to recordfrom into Metro. Select Built-in to use the sound input on your Macintosh as a record source. Built-in is the standard setting if you are using the built-in audio hardware of your Macintosh and not a dedicated audio card. If you have a Korg 1212I/O, Sonorus StudIO or CoreAudio compatible sound card installed, select the card’s input port in the Direct Support pop-up to designate it as your record source.