We are aware of this issue, and have come to the conclusion that this is an issue with a program on peoples program - it varies, so I can't tell you exactly which program. (We have gotten reports about Nahimic and Sonic Radar-it can also be another Asus factory installed sound softwae- for example)
Try disabling programs that aren't vital for the PC to run until the sound appears. Do note that it's typically an issue with your sound drivers or programs installed on the PC from new, so try disabling those first. Also make sure you run Steam as admin! You can also check the link out below.
https://wiretuts.com/how-to-fix-no-sound-problem-in-steam-games/