Sound therapy refers to a range of therapies in which sound is used to treat physical and mental conditions. One of these therapies is music therapy, which can involve a person listening to music for conditions such as stress and muscle tension. Music is one component of this therapy. In this therapy, sound wave vibrations are used to treat physical and mental conditions. In general, this therapy is based on the theory that all of life vibrates, including people's bodies. When a person's healthy resonant frequency is out of balance, physical and emotional health is affected. Treatment by sound waves is believed to restore that healthy balance to the body. Healing is done by transmitting beneficial sound to the affected area. The healing sound may be produced by a voice or an instrument such as electronic equipment, chanting bowls, or tuning forks.