When you have so many people sitting in a concert but you just suck in singing live ...

Half of this is just the playback running in the back and he ain't singing ... it's forbiden to fake singing in Japan so they all have to do live singing, but you clearly see how the track plays and he just only sings half of it. And about the live singing, it's forbiden to let it look like you sung the song, so what KPop groups mostly do on TV would be not allowed in Japan and they do have to sing the entire song themself on stage in Japan. But what Noa does is ... imagine you buy expensive concert tickets, than he only sings half of the song ...