Android Head Unit GPS volume really really quiet?

Hi, just brought my mum a Eonon GA1312 Android head unit, I've set the majority of it up and brought a lifetime service for Sygic Navigation for offline maps, it seems when playing the radio the directions on the GPS being said sounds like its coming out of a separate speaker or something, this applies to both Google Maps and Sygic, I highly doubt the directional commands aren't coming from a separate speaker, but the volume is absolutely dreadful, you can literally just hear it, I haven't tested this head unit properly yet but I've heard the directions speak out a lot louder while dimming the background music of Spotify, can anyone help me with this problem? I don't want my mum not to be able to listen to the radio while using the GPS Navigation just because we can't hear it. Thank you.

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