Plug the USB end of the adapter directly into your Mac (or via a USB-C dongle).
Connect a standard 5-pin MIDI cable from the port on the back of the Radium 49.
Note: This method generally fails on Apple Silicon (M-series) Macs due to strict security policies and different chip architectures. Troubleshooting Common Radium 49 Mac Issues Keyboard Powers On But Sends No Data
Modern macOS versions (Catalina, Big Sur, Monterey, Ventura, Sonoma, and Sequoia) run exclusively on 64-bit architecture. They also support Apple Silicon chips (M1, M2, M3, M4).
This design choice made sense in the early 2000s, when dedicated drivers were common even for consumer‑grade gear. M‑Audio included a driver CD with every Radium 49, offering support for Mac OS 9, OS X (10.2–10.4), and various Windows versions. Today, the official drivers can still be found in the “Legacy” section of the M‑Audio support website, but they are all 32‑bit executables that will not run on macOS Catalina (10.15) or later.
Open Audio MIDI Setup (found in /Applications/Utilities/ ). If the driver is working, the Radium 49 should appear as a MIDI device in the MIDI Studio window, typically labelled “Radium” or “M‑Audio”. If it does not appear immediately, click the “Rescan MIDI” button in the toolbar.
There are no official drivers for current macOS versions. Users on macOS Ventura or Sonoma will find the device is not recognized when plugged in directly via USB.
to a modern, class-compliant USB MIDI interface (like those from iConnectivity
M-Audio Radium 49 is an "end of line" product, meaning official driver support has ceased for recent macOS versions. If you are using a modern Mac (macOS Catalina, Big Sur, Monterey, Ventura, or Sonoma), it will likely not work via a direct USB connection because it is not class-compliant and requires legacy drivers. Apple Discussions Compatibility Status Officially Supported: Up to macOS 10.8.5 (Mountain Lion). Last Known Working (with Drivers): Some users have successfully used the MIDI USB Driver v3.5.3 on macOS Mojave (10.14) or Yosemite (10.10.3). Incompatible:
having trouble with a radium 49 key stati… - Apple Community
The most reliable way to use a Radium 49 today is to bypass its internal USB interface entirely:
No official drivers exist. The USB port on the keyboard will likely only provide power, not data. 2. The Universal "No-Driver" Workaround
: Unlike newer Keystation models, the original Radium 49 is generally not considered fully class-compliant for modern systems, though some users have had success with workarounds.
Bome MIDI Translator Classic (free) or Pro (paid) is the definitive solution for legacy MIDI controllers. It acts as a virtual driver, listening for the Radium’s proprietary messages and translating them into standard MIDI CC that any modern Mac app understands.
