It seems the static sounds are caused by incorrect grounding. My speakers and Raspberry Pi runs of the same power adapter and whenever I change that so that they run of two separate adapters everything works good.
The settings I made to /home/pi/RetroPie/configs/all/retroarch.cfg are the following:
audio_enable = true
audio_out_rate = 44100
audio_driver = sdl
audio_sync = true
After these changes were made and after a reboot everything worked good. Now I get perfect and clear sound/music in all my games.
Also make sure to overclock your Raspberry Pi. I’m running mine on 900Mhz (Medium) and everything works great. You can try without, but people recommend overclocking on order for the audio to work good.
I also followed this guide (http://raspberrypi.stackexchange.com/a/5611) in order to update the kernel to the latest version with updated audio drivers.
Let me know if my suggestions worked!