UPDATE I decided to kill the boom box as it has a mike channel in it, so as soon as I kill the HK GO PLAY (disabled in sound panel in device PC) the Benq screen audio works and plays while recording !!, I now know why. the OBS studio prevents howl around (feedback) as it simply cannot kill the boom box mike, so it automatically disables the audio, if it left the audio monitor running then the internal mike of the BoomBox would feedback/hwol around, even if you MUTE the mike there still is no monitor audio. In my PC ive selectivly disabled the boom box's mike (harmon kardon) its grey out BUT OBS still finds it soemwhere That's causing the problem. OBS does not kill the mike THUS allowing audio in the box, or room, etc. Try it, use another audio device and PULL OUT DISABLE all micorphones your audio will probably work ok.
