I am using a USB-C to USB converter on my iPad Pro 2020 to connect my keyboard to audiobus, and then to Loopy. That converter also has a 3.5 jack on it so that I can get sound from my iPad.
Unfortunately, the first time I run Loopy from Audiobus (or sometimes even when it is run standalone), there is a horrible feedback sound that ruins the whole experience that lasts around 2-3 seconds. As I understand it, Loopy doesn't mute the iPad microphone until it is run and detects that the setting is off and there is a delay before it realizes that the jack is supposed to be active and not the on-board speakers.
Could you please fix this issue? I would gladly give you more details if needed. I am sure there are other people facing the same problem.