"As Jackson couldn’t fluently play any instruments, he would sing and beatbox out how he wanted his songs to sound by himself on tape, layering the vocals, harmonies and rhythm before having instrumentalists come in to complete the songs."
“Steve Porcaro once told me he witnessed MJ doing that with the string section in the room. Had it all in his head, harmony and everything. Not just little eight bar loop ideas. he would actually sing the entire arrangement into a micro-cassette recorder complete with stops and fills.”