For advanced users, there are open-source efforts on GitHub that attempt to implement drivers for legacy M-Audio (MIDISport/Radium) hardware on modern macOS. Troubleshooting
Version 3.5.3 is the most recent release, originally designed for older versions of OS X.
The M-Audio Radium 49 is a piece of history. Released in the early 2000s, this 49-key USB MIDI controller was a staple in home studios, known for its semi-weighted action, dedicated transport controls, and eight assignable knobs and faders. For producers who came of age during the Reason 2.5 or Ableton Live 4 era, the Radium series holds a nostalgic, almost legendary status.
