Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Roku just supplies the hardware and two channel apps to run on it (The Roku Channel, and Roku Media Player). All other channel apps are supplied by the channels themselves, and any settings and controls are what they have programmed in. What audio app are you talking about? Maybe somebody who actually uses that app will know if specific radio stations can be bookmarked or saved as favorites.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T