Resonant tuning, the use of binaural beats, and related sound therapy have been used to entrain brain waves states such as alpha, beta, delta and theta and induce spiritual healing. The premise behind sound therapy is that objects and living beings have their own states of resonance. When vibration is in balance the body is healthy. Through light and sound devices, cranial electrostimulation or Hemi-Sync, a body that is out of balance can be entrained to specific resonant frequencies to help return it to a state of health.

The use of sound for healing dates back eons. For centuries, music and light have been central to healing, spiritual practices and sacred traditions. Shamans chanted and drummed to heal people. The mystical schools of early Egypt, Greece, India, Egypt used sound and music for healing. Sonic vibration is still considered by many people to be the fundamental creative force in the universe. Some of the research supporting the ideas of sound healing was conducted by the Swiss medical doctor Hans Jenny. His experiments into "cymatics" have demonstrated how various substances, for example, plastics, liquids and sand would take on different shapes depending upon the frequencies to which they were subjected. Dr. Jenny's experiments showed that sound has the ability to affect and change molecular structure.

• Hemi-Sync® - synthesized sounds designed to: 1) to synchronize the hemispheres of the brain, more or less as you state above, and 2) to "entrain" certain specific brainwave frequencies, which correlate to particular states of consciousness (the Monroe Institute, which developed Hemi-Sync, calls these "Focus states" to avoid the confusion of trying to borrow other nomenclatures that carried unnecessary contextual baggage). Particular Hemi-Sync signals tend to enable the participant to reach these brain-wave states, and then reach these states of consciousness, which in turn makes certain kinds of metaphysical and/or spiritual experiences possible, or at least, a lot more likely. These can include (but are not limited to) contact with spirit guides, out-of-body experiences, visitations with "angels" (no inherently Christian dogma implied), contact with extraterrestrial intelligences, experience of past/future/other lifetimes, etc.
  
  
• Bio-Acoustics - using specialized software, missing frequencies of a person's voice are found, recorded and recorded via synthesized sounds.
  
  
• Cymatic Therapy - specific frequencies via an electronic instrument are projected into a person's body to create physiological change.
  
  
• Electronic Ear - a person will listen to a program of specially filtered music via headphones, designed to open the ear and brain to greater frequencies of sound and treat imbalances in emotional and learning states.
  
  
• Harmonic Resonance - testing using kinesiology and the reception of synthesized sound to achieve physical balance.
  
  
• Vibro-Acoustic Furniture - a person may sit or lie on a specially designed object that projects music into their body.
  
  
• Tuning Forks - specific sound frequencies designed to produce relaxation and balance.
  
  
• Mantric Chanting - using specific sound mantras to balance and align energy fields.
  
  
• Toning and Overtoning - a person may receive the vocally created sounds of a practioner to balance and align imbalances on the physical, emotional or spiritual level.