Double sound when testing mic audio

I have this same issue, I use obs and vb cable to adjust my input audio that I pipe into programs, but I believe it only picks off my windows default input (a usb mic) for the mic test. (I have yet to test actual calls because I was trying to figure out this exact issue haha) I found that the echo would go away if I switched my output device in fluxer to a speaker that could not output audio. I'm not a programmer, but my feel playing around is that it is playing back tester audio in both the windows default and the output device selected in fluxer, if fluxer is using the same output as windows it doubles up to form that echo. If fluxer uses something different from the default, I ran into sound coming out my headphones and the speaker in my monitor. System: Windows 11 Home