I found this when trying to figure out the issue myself. I see the suggestions provided were not overly helpful. It is an issue with your bit rate/bit depth not being compatible with the xbox party chat.
Right click sound icon on bottom right, select recording devices, highlight your mic device, select properties, advanced tab, change bit rate to DVD quality 2 channel 16 bit 48000 hz.
Now just make sure the xbox app is still set to the correct device and it should clear up the awful buzzing.