Muffled Vocals on iPhone

[Mitchiet41]

Hi Everyone,

Just downloaded Spotify Premium under a Free Trial for 7 days.

When I play audio out of my iPhone 6s through speakers the audio is completely fine. However as soon as I plug in earphones to listen, the vocals become muffled to the point where I can barely hear them, especially in songs with a loud backing track. The rest of the song remains the same mind you, just the vocals are much quieter. Does anyone know how to fix?

Thanks guys