New speaker makes loud sound after installation

My gf's Moto G 2nd Gen has the lower speaker that makes loud noises, so I bought two new ones and proceeded to change them.

Even the new one makes that sound.

Thing is I think they both work correctly.

Why?

If I change the lower speaker with the upper one, the results are the same but if either one of them is put in the upper position they both work.

I wanted to test this thoroughly so I did it with the phone on, before putting back the screws.

I found out that holding the back cover without the screws both speakers work perfectly, but when I put back the screws the speaker starts distorting sounds again.

So in the end my question is: there is a way to fix it?

Thank you for your time ;)