Sound therapy uses instruments or pre-recorded tones to produce sounds that soothe listeners into a state of relaxation. Instruments commonly used during sound therapy sessions include Tibetan singing bowls, crystal bowls and tuning forks.
Pre-recorded sounds are often designed to deliver two tones at a different frequency into each ear. This causes the listener to perceive a single tone that varies in amplitude at a frequency equal to the difference between the two tones. The single tone perceived by the brain is known as a binaural auditory beat.
These types of sound therapy haven’t been as thoroughly researched as music therapy. Though few clinical studies have scientifically investigated sound therapy, people say it promotes deep relaxation, enhances learning, improves sleep and reduces perception of stress. Studies on binaural auditory beat suggest it may improve sleep, memory task performance, attention, relaxation and mood.