Weak sound in earpiece since a ROM update (MIUI9 and MIUI10 also happening)

May 18, 2016
I installed the some monts ago a ROM in MI5 and suddenly I started to have a very low volumen in the earpiece. At the begining I though it could be the earpiecec and I replaced it....but still the same.
So I installed the last stable ROM ( to check if it was fixxed but not....
I saw a thread here were it was giving a workaround and after doing it (MIUI 10 stable - weak sound during calls - SOLVED! ) the volume was improved but it is still low and we I am in a noisy place I cannot heard....and even when I am in a quiet placce the sound is scratchy and quality not so good.
I wonder if somebody has found another way to increase the volume.....