I have two iPads - a 9/7" Pro and the latest standard 10.2" iPad. Both have the 8mm port, which I use to hear myself with the monitor in GarageBand. I use the lightning port for a portable, compact Shure microphone that was launched with the 9.7" Pro many years ago.
I've not updated to the more powerful iPad models because they don't have the 8mm port. So I have two iPads, neither are what I want, one too old, the other not powerful enough for some other editing work I do. If I can find an adapter that allows audio output and sound input at the same time, I could trade in both iPads for a new Pro and use the adapter.
Does anyone know of an adapter to plug into the lightning port of an iPad that supports audio input through lightning and audio output through an 8mm port?