Okay, I solved the crackling issue.. After all tries, the problem was the bootloader.. I used Chimera, Chameleon, Clover.. I installed all kinds of bootloaders and then I tried to boot from the USB's bootloader (Clover, version older i think) and the audio was crackling just a bit.. I enabled SSE2 and now it's perfect. I moved the USB's Clover to EFI of my main volume and now it's all good with sound..
Just a silly question.. Everytime I restart my computer I have to enable SSE2 and to put 48000 Hz in Audio Midi Setup. Is there a way to make that change forever? Because it's a bit boring to always check that every time I restart my pc? Other than that, it's great!
Thanks pernacabeluda for everything!