Self-described "loner" says he found the experience to be "quite moving"
"Your job as an audience is to bear witness ... to come open and willing to transform," says Oscar-winning actress
Singer also became first artist to Periscope live in 360 video, giving look at her Super Bowl green room
Singer gave passionate speech at Convention of the Rights of Persons with Disabilities
Los Angeles indie rock band will release third album 'Heads Up' next week