Sounds.then Comunications in Control panel. Windows can automatically adjust volume if you use your computer to place or receive telephone calls.
Not sure if that is what is happening to you but it can be adjusted if so.
OnePlus 5T review: Hands-on
Illustrator Andrés Lozano on his improv line work, brazen use of colours & hand sketching
iPhone X review
Comment envoyer gratuitement des gros fichiers ?