Default [Q] Samsung S4 Speaker and static problem

Hey
I bought a t mobile Samsung galaxy s4 (SGH-M919) with a cracked screen.
I replaced the screen and I am now encountering a problem.
There is a weird staticy sound that is coming from the phone. It seems like a sound that is coming internally.
Also , my speaker was not loud so I ordered a new one and replaced it.
I am still having the same problem.
The static and low sound.
Does anyone know what could be the problem and maybe the fix ?
Thanks in Advance