Mariah Learns Humidifier Trick From Luther

Pop diva [Mariah Carey](https://www.contactmusic.com/mariah-carey)'s penchant for sleeping in a room full of humidifiers the night before a concert is a vocal tip she learned from late soul great [Luther Vandross](https://www.contactmusic.com/luther-vandross).

The singer has often been ridiculed for her vocal demands, but she insists she has to take care of her voice.

She explains, "I sleep as much as I can the night before (a show). We have to sleep to hit the notes.

"I need humidifiers when I sleep because it's good for my voice. Luther Vandross, God bless him, told me that."