There is a gain button to the left of the PTT button. If you tap that, it will display a slider that you can adjust the gain up or down. I would suggest using a parrot node to test and see whether it's actually your phone or the node that you're connected to. For example, I know that there is a repeater nearby me that, when anyone connects via EchoLink, the audio is super quiet. It's actually the reason I added the gain in the first place. But in that case, the problem is in the audio connection between the computer and the repeater hardware.
- Wes W8WJB