Your Motherboard Audio device ALC1220 is reported to work well with a recent kernel
Your ALSA information shows Kernel 4.14.74
Manjaro is currently on 4.14.87 kernel, so you need to update your system first
A more recent kernel will have better support for Ryzen
suggest use Manjaro Settings Manager to add latest kernel 4.19.8
(don't need to remove other kernel, can keep it as a backup)
ALSA information also shows master level for audio device turned down:
Code:
Playback 60 [69%] [-20.25dB]
If audio is distorted, it is likely volume level is set over 100% in Pulseaudio
but reduced volume in ALSA keeps it from being too loud
Suggest turn down audio in Pulseaudio Volume Control first
then go to:
Code:
alsamixer --card 1 --view Playback
and turn Master level up