"Hands-free telephony is that little option that shows up when your bluetooth headphones also have a microphone and windows detects it as a headset which makes the audio output quality terrible and unreasonably loud when your microphone turns on. if this has also happened to you, you can look up a guide on how to turn it off, though you won't be able to use your built-in mic if you take the easy route and just disable the option in the properties menu."