@Eddie,
"When I plug in a headset with a mic in the 3.5mm port, it still seems to use the internal mic instead of that of the headset."
What happens if you manually select usb headset from gnome-sound-setting->input devices.
@Eddie,
"When I plug in a headset with a mic in the 3.5mm port, it still seems to use the internal mic instead of that of the headset."
What happens if you manually select usb headset from gnome-sound- setting- >input devices.