we have a same problem for FPS Drop after sound update. I uploaded this video for the fix this problem. And this solution solved my problem.
If this doesn't work for you. Please restart your PC. It should work after that .
If you still cant solve it, i can help you. Write comment under this video. Thanks for watching.
Command : ""+snd_use_hrtf 0""
Song : Jacob Tillberg - Apocalypse
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