AUM (Audio Unit Mixer) is an incredibly powerful iOS audio hub, but handling its internal and external clock systems can quickly become frustrating if devices drop sync, drift, or refuse to communicate.
The most important rule to remember is that AUM is fundamentally designed to act as a MIDI Clock Master, not a Slave. Trying to force it to listen directly to standard external MIDI clock signals from hardware or other DAWs will fail. 1. AUM Won’t Follow External Hardware/DAW Tempo
The Cause: AUM natively blocks incoming traditional MIDI clock signals to ensure system stability. The Quick Fix: Use Ableton Link as a bridge. Turn on Ableton Link and Link Start/Stop in AUM’s top menu.
If your hardware or DAW (like Cubase or an MPC) doesn’t support Link directly, load a bridging application like Loopy Pro or Audiobus in the background.
Route your external hardware MIDI clock into the bridge app, and allow that app to convert the timing into an Ableton Link signal. AUM will instantly lock onto the bridge’s tempo. 2. External Gear is Drifting or Out of Sync
The Cause: Standard USB MIDI clocks inherently suffer from jitter, or you haven’t explicitly targeted the outbound signal. The Quick Fix: Check your explicit MIDI Matrix routing. Tap the Tempo/Metronome icon at the top left of AUM. Tap the three dots and toggle MIDI Clock Send to “On”.
Open the MIDI Matrix (the routing grid icon) and verify that AUM Clock Output is wired explicitly to your destination hardware interface or USB port. Do not rely on “All Outputs.” 3. Audio Units (AUv3 Plugins) Are Not Syncing to the Grid How to sync Loopmix as AUv3 with drum machines – Facebook