If you're using the Smaart IO audio interface with an older version of Smaart, you'll need to download the Control Application to manage gain, phantom power, and polarity inversion controls.
Please note: if you're using Smaart v8, Di v2, or SPL, you do not need to install the Control App as all the controls can be found natively within the program by navigating to View > Input Meters > Input Meters