Just tried this - the MIDI app already shows Series 800 selected. Clicked again to make sure and hit play - no sound thru Meridian speakers.
Did not work for me.

Next, I will take a circa 2015 Macbook with a USB output to connect directly to the 818v3. Previously it was a current Macbook with USB-C out to a hub and from hub I used a USB cable to the 818v3.

Primary system: 818v3, DSP8000 40th SE, Linn Klimax streamer, Esoteric CD

2nd system: DSP7200, 7200HC, 861v8