Our VAS(VirtualAudioStreaming) works for your purpose, in fact, it is designed for this.
You can view the below article to see how to configure VAS to sing karaoke on website:
http://www.virtualaudiostreaming.net/stream-broadcast-sounds.htmlIn short:
1) open paltalk configuration dialog and set VAS as its input microphone. Something like below picture, I use Skype as example:
2) open VAS main dialog and select your real microphone like the below picture:
3) set VAS as the default system playback device:
4) done.