How to connect an external mic/synth/guitar to the Android/iOS device?
Русская версия здесь
There are several ways.
- For high quality sound - use some external USB audio interface.
- Use headphone jack of your device (3.5mm TRRS, 4pin) with adapter (there are many different ones; just search: headset mic splitter adapter).
- Build your own adapter for headphone jack (3.5mm TRRS, 4pin). The circuit diagram is below.
Note that the GND and the MIC pins may be swapped on some non-iOS devices with OMTP standard!