Ben
Hi Ben, thanks for your question.
The built-in and external microphones are connected to the same input circuit. The built-in mic is enabled by default, and when the external mic is plugged in, both mics pick up sound at the same time — the system does not automatically switch between them.
If you want to disable the external mic, simply unplug the external microphone cable from the back of the unit. After that, only the built-in mic on the front panel will work.
