Microphone works in other Source Games, but not in Team Fortress 2

[Knight Vista]

Be advised i've already searched the fuck out of Google, i'm completely oblivious as to how or why this happened. Nor do I know how to fix it.
I found the problem when people would talk to me but they said they couldn't hear me.

I haven't played TF2 in forever so I have no idea when the problem started, because I just now got back into it.
Any help would be nice, hopefully you can let me know how to fix this.

[cardboardtheory]

Have you tried the usual rounds first? Check game integrity, check microphone settings, delete clientregistry.blob, reinstall TF2...etc.