I can’t remember the last time I watched live concert. I think a decade ago if my memory is right. I would be happy if i could watch my favorite artist performing live on stage once again. I noticed there are singers who are using earphones while performing; I guess it is in ear monitor system. It is type of headphones usually used by live performers. Onstage monitors are unreliable, loud, disturbing using in-ears guarantee that musicians hear the mix they need to deliver the best possible live show. It also serves as an effective blocking external noise that musicians are literally deaf to audience applause, even at stadium shows.