Sound masking is the addition of sound created by special digital generators and distributed by normally unseen speakers through an area to reduce distractions or provide confidentiality where needed. The sound is broad band random that conveys no information about itself to a listener. It is often referred to erroneously as white noise or pink noise; the sound spectrum and level is specially shaped to provide the degree of privacy desired by occupants. Masking operates by covering up or masking unwanted sounds, similar to one-way windows that block the ability for a person to see persons behind them, or perfume that covers up other body odors. This is in contrast to the technique of active noise control which attempts to eliminate the unwanted sound. Sound masking is used in homes, commercial offices, medical facilities, court rooms, and in secure facilities to provide secrecy. It also can be used outdoors to restore a more natural ambient environment.