I just installed Vegas Pro 19 (after being totally disappointed and wasting 59$ upgrading to Movie Studio 18 Platinum)
I started the program and loaded a project previously created in MS18P. When I previewed the project the audio came out as a horrible hissing sound. Now anytime I play a file, inside or outside Vegas, (youtube, mp3 audio, mp4 video) it exhibits the same horrible hissing sound. I can reboot the computer and files play/sound normal again. Start Vegas Pro 19 and the hissing starts over again.
Dell XPS 15 759/Intel(R) Core(TM) i7-9750H/Windows 10 Home 20h2/Vegas Pro 19, Build 381/Nvidia GeForce GTX 1650