Apogee Rosetta 800 Converter - confirm the following front panel settings before continuing
Sample Rate - EXT
Sync - WC
Source to Digital Outs - ADAT
Source to Analog Out - ADAT
Apollo X8
Outboard Effects
Neve 8816 Summing Mixer
Mac Mini M1
Speakers - power outlet switch on wall near door
The Neve 8816 has a 3.5mm input labelled iMon. Connect your device, typically using a 3.5mm to 3.5mm cable
Press the 'MON' level control at the bottom right of the unit to cycle the monitor source until it lands on iMon
The Apogee Rosetta 800 outputs 1-8 arrive at the 8816 on channel inputs 1-8 via the patch bay normalling
The Apollo X8 outputs 1-8 arrive at the 8816 on channel inputs 9-16 via the patch bay normalling
Ensure your audio software is using Universal Audio as the playback engine and output 1-2 from the Rosetta 800.
The 8816 allows you to select '1-2' as your monitoring source, which bypasses the mixer. Do that.
Use the input and output meters on the audio interfaces to help with troubleshooting
Neve 8816 Manual [from the AMS-Neve website]