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Applied Psychoacoustics

by | Jun 12, 2010

In last week’s blog, I described aspects of the field of psychoacoustics in general. This blog focuses more specifically on applied psychoacoustics.

The term, applied psychoacoustics has been used to describe music that has been created using psychoacoustic knowledge and principles to make a specific change in your physiology, your mental state or your mood. Music producer, Joshua Leeds, is a world authority on applied psychoacoustics. His book, The Power of Sound, is an excellent source of information on this subject.

There are four ingredients of applied psychoacoustics:

  1. Resonance is the frequency at which something naturally vibrates. If I tap a table, you hear the natural resonance of the wood. Similarly if I knock on a wall or a metal door, we hear the resonant frequency of the wall or the door. Everything has its own resonant frequency. Including you.The tiniest parts of you, your atoms and molecules, have a specific resonance. A blood cell has a different resonance than a bone cell. Your stomach has a different resonance than your liver. Your skin has a different resonance than your muscles.

    Forced resonance or sympathetic vibration is the impact of a sound, rhythm or frequency on another. For example, if I tap a tuning fork and place the stem of the fork on a table, it will now resonate to the sound of the fork and not the sound it would make if I tapped it.

  2. Entrainment is the use of a stronger pulse to create a change in another. The main physical systems entrainment affects are heartbeat, breathing, and brain waves.Rhythmic entrainment is one of the methods used on CDs of music in the applied psychoacoustic genre. The rhythm is used to stimulate you or to slow you down, by speeding up or slowing down your heartbeat. For example, if the intention of the music is to create relaxation, the rhythm will be at the speed of a relaxed heartbeat. When you affect the heartbeat, you also affect the breathing rhythm and the rhythm of the brain waves. These three systems are deeply connected.
  3. One example of Sonic neurotechnology is the use of sound technology tostimulate specific brain wave frequencies. This is called brainwave entrainment.Here is an explanation of how it works. A frequency, for example, of 440 Hz is placed in the right ear only. A frequency of 448 Hz is placed into the left ear only. When you listen to these sounds through headphones, a very interesting thing happens to the brain. The brain hears a third tone. Actually it is more of an electrical signal than an auditory one. That tone is the difference between the frequencies of the two sine waves. That is, 448 Hz minus 440 Hz equals 8 Hz.

    These tones sound like they are wavering, similar to wavering in the singing bowl or tingshas. This third tone, the 8 Hz in this example, is called a binaural beat. Since 8 Hz is below the range of human hearing, the only way the brain can acknowledge this tone is if both hemispheres of the brain are connected. The act of listening to this wavering stimulates the two halves of the brain to connect.

    This effect on the brain is called hemispheric synchronization. That is, the hemispheres of the brain connect and begin working together in order to recognize this difference between the two sounds. Magnetic resonance imaging results of the brain in this state of synchronized hemispheres show a huge increase in the activation of areas in both sides of the brain.

    The result is that the brain wave state shifts into the frequency of the difference between the two sounds, quickly and easily. In this example, the difference is 8 Hz, which is in the Alpha range. The listener shifts into a meditative state effortlessly.

  4. Intention is the focus of the results expected from listening to the music. Examples of intentions for recordings are relaxation, reduce stress, help you sleep, calm the body and focus the mind, boost the immune system, balance the chakras.Many of the CDs produced in this genre change the speed and/or instrumentation of classical music to achieve the desired heart rate or brain wave state.

Applications of psychoacoustic music are diverse and useful. Recordings can help you:

  • Go to sleep
  • Relax better
  • Learn faster and remember what you learn
  • Increase your productivity at work
  • Inspire you or help you think more clearly
  • Focus and concentrate for longer periods

Psychoacoustic music in clinical use can help people with the following conditions.

  • Learning disorders
  • Attention disorders
  • Auditory processing disorders
  • Autism
  • Speech and developmental delays
  • Stroke and motor problems

Where to find high quality CDs that use techniques of applied psychoacoustic music:

I will discuss music that uses brainwave entrainment frequencies in a future blog. Examples of this music will be given there.