You may use an external audio source with your Mevo, via your iOS device's TRRS 3.5mm plug or the USB port in a Mevo Boost.
The TRRS plug is a specific type of plug. The easiest example of what one looks like is your iOS device's supplied earbuds. If you look at the plug on your iOS earbuds, you will see three rings. Any audio output you want to use with Mevo must have these three rings, as this is an iOS device requirement.
More information about supported external audio inputs is available here.
Plug your TRRS 3.5mm audio input into your iOS device's headphone jack.
Once you have connected your Mevo to your app, open the main menu by tapping the 'More Options' icon (three dots) in the bottom right corner of the live edit view. The below menu will appear.
Next, tap on the Audio Mixer icon.
In the Audio Mixer, you will see "Mevo" is selected, and "iPhone" is greyed-out.
Tap where it says "iPhone," to start using your external audio input.
You will see your audio levels in the green bars to the right.
Note: When inputting a stereo signal into the iPhone through the 3.5mm TRRS input, the output will be a mix of the left and right audio channels.
When inputting a stereo signal into the iPhone through the Lightning port, the output will remain in stereo.
When using an external audio source, you cannot also hear your audio output through the app. You will have to monitor the audio on your live stream.
You can adjust your audio gain up and down with the slider bar to further adjust your levels.