No Loudspeaker audio? iPhone 6

Hi,

I have a iPhone 6 that has been having some problems that seemed to be software related such as not being able to play vid?eos or make calls. Now I am experiencing this problem where the is no audio from the loudspeaker, however the earpiece works fine.

When I press the volume buttons, nothing happens on the display. When I try to play music or watch a video, it looks completely fine but I dont hear anything. However, if I try to play audio over Bluetooth or headphones it works fine and when the volume buttons are pressed it shows on the screen.

It seemed to me that the actual speaker was not working and not being recognized by the phone, so I bought a new one however swapping out the one that should be working fine had no effect on the problem.

So what do you guys think is causing this? a problem on the mainboard or a software problem? or something else? Thanks for your replies.