This is an addendum to The Stand-alone Host “Rack” page.
LOGIC
In order to avoid MIDI feedback loops when using the IAC
bus, open the “Environment” window and select “Click & Ports”. Highlight the cable that goes from the SUM port
(located in the Physical Input box) into the Input Notes keyboard and delete
it.

Click to enlarge
Create a cable that goes from the Physical Input port where
your MIDI controller is connected (in the image below it is labeled as “Port
2”), and connect it to the Input Notes keyboard.

Click to enlarge