Same EQ settings and no volume limit and the same headphones are used but the problem is not just for these headphone it is for all earphones i used in the past and use now so the iPhone's earphones jack is the problem's source and i wonder if i can make it release more power (louder volume) in anyway
If that's the case, then you should opt to have it diagnosed in a local Apple center. If pressing the volume buttons on the side won't work as well as increasing the volume via Settings, then I guess a hardware issue's taking place.
