Having spent 'some' times in a studio, actually, you can get an audience to respond, and make it seem genuine. 'Applause' lights and guys who signal, like cheerleaders, off, usually to the sides..but not too far. That being said, I think the enthusiasm for Susan, was quite a bit spontaneous....however, if the audience had a large monitor, showing the judges re-action, that certainly would have helped the momentum. When I watched it, several times, I admit, it got me to tears.