PulseAudio is using onboard audio device alsa_output.pci-0000_0b_00.4.analog-stereo as default sink for audio playback and the Monitor of the onboard audio playback as default source for audio capture
Use this command to set headset as default sink for audio playback
pacmd set-default-sink alsa_output.usb-Kingston_HyperX_Virtual_Surround_Sound_00000000-00.analog-stereo
and this to set headset microphone as default source for audio capture
pacmd set-default-source alsa_input.usb-Kingston_HyperX_Virtual_Surround_Sound_00000000-00.analog-stereo