I have copied this from my post in the NativeInstruments forum, so apologies if you have seen this there, no answers syndrome!
Firstly apologies if this has been covered before, I have had a good search first and RTFM!
In Cubase 9.5, if I set main output as MAIN L+R I can hear the output in the headphones aswell. Odd, as I can also set the main output as Headphone L+R and the the Main L+R goes quiet (as expected). If I then turn off the main output completely and go to Control room, set monitor as Main L+R I hear Main output in speakers to which I now have a volume knob, great! But I hear output in headphones, rubbish. If then in addition I set headphones in control room to be Headphone L+R I get a volume control for it as I do with Main but basically this just makes my headphones louder. So if i turn knob for headphones to off and main is still coming out of speakers, I still get headphones but quieter.
So in short, Main always outputs to Main in Maschine AND Headphones, not JUST main. If i set it up to just be headphones all works fine as expected send audio to headphones and I hear NO output in main.
I wonder how the audio is setup for anyone in this same scenario? Or is it usually this way?? Seems really bloody odd!!!??
Thanks in advance!