Same thing on Zen 1700 3.95GHz | 32GB 3474Mhz CL14 | Vega LiquiD | SB-Zx + Audio-Technica ATH-AD1000X
To replicate this bug, just crank up Volume to min. 75% and scroll Web Page for example in FireFox.
This is known issue with AMD/ATI (it's not fixed to this day)
The same thing is for Phenom & FX also, so it's not only Ryzen.
One note tho:
It's fine when You launch Game or Movie/YT the buzzing sound is gone (at last for SB Card)