Note: This section was adapted from material originally written by Joshua Leeds, co-producer of The Listening Program and author of Sonic Alchemy and The Power of Sound.

What is Sound?

In order to understand how music and sound can produce such powerful results, we need to first take a look at the medium of sound. Sound is a waveform that alters the compression and rarefactions of air molecules. Perceived primarily through the ears, sound is transformed into electro-chemical impulses in the inner ear and sent to the brain. Processed in numerous auditory centers of the brain, sound connects us to our environment, alerts us to danger, allows us to understand language, and enables us to speak and be heard. Sound is the raw medium from which laughter and music evolve.

The substance of sound is amplitude and frequency. The amplitude of a sound wave is related to loudness and is measured in decibels: the greater the amplitude, the louder the sound will be. The frequency of sound waves, measured in Hertz (Hz), determines the pitch of the sound, with higher frequencies corresponding to higher pitches. We have the ability to perceive sound waves within the range of 20 to 20,000 Hz, from the lowest sound you can imagine to the highest.

Our relationship to sound has extraordinary characteristics of its own. Most notably, humans have the capacity to make sound in addition to perceiving it. We come equipped with the mechanism to take sound in through our ears and send it back out with our voice. Because of this dual function, we have a unique connection with the medium of sound that is different than that of taste, touch, or sight.

Sound provides a non-tangible yet highly personal connection between people. Our primary form of communication is through the production of language, songs, tones, and noises. The diminishment or loss of this contact often makes social maturation and emotional relationships quite difficult. As a predominant element of human interaction and exchange, sound is a currency of tremendous value, and our hearing is more precious than we tend to realize.

How Do We Hear?

The hearing system or auditory apparatus consists of three components: the outer ear, the middle ear and the inner ear. The outer ear is separated from the middle ear by the eardrum or tympanic membrane. Hearing commences when sound enters the outer ear and passes through the ear canal. The air vibrations of sound then strike the eardrum, which sets off vibrations in the three tiny bones of the middle ear (the hammer, anvil, and stirrup). These vibrations continue into the cochlea, located in the inner ear, where thousands of tiny hair cells transform the vibrations into electro-chemical impulses that travel to the brain. None of these auditory impulses go directly to their final destination in the primary auditory cortex, as they are processed in many levels of the brain before arriving there.

The snail-shaped cochlea is the basic organ of hearing. This fluid-filled chamber, with its very sensitive hair cells, responds to the pitch, intensity, timbre, and duration of tones, allowing us to appreciate music as well as the emotional content of language.

In addition to hearing, the inner ear, also known as the vestibular system, is responsible for control of balance and posture, and is necessary for coordination and precise motor execution. It responds to gravity, rotational movements, and changes in acceleration. The vestibular system operates in the realm of the unconscious, and is connected to the auditory and visual systems through the nervous system.

The proper functioning and organization of the vestibular system is essential to all higher learning, eye-hand coordination, rhythm, and a sense of the body in space. Therefore, any dysfunction of this system interferes with handwriting, reading, sports, and almost any activity we can imagine.

Auditory Training

Auditory training is different than music therapy. Music therapy focuses on the psychological effect of music and music making, as relaxation and comfort are derived from the familiarity of the thematic content or the making of rhythm. Auditory training, on the other hand, is based upon the neurological effect that sound has on the nervous system. A cortical charge takes place with the direct application of sound waves, especially when applied through headphones. While MFM II uses improvisational music that does have a therapeutic benefit, its primary purpose is to deliver filtered and non-filtered high-frequency sounds to the ear and brain. The process of auditory stimulation reeducates the hearing mechanism to take in a full spectrum of sound.

In auditory training, the effect that one vibration has on another, known as resonance, is key. In this instance, resonance can be thought of as the ramification of sound vibrations upon our physical bodies. We know, from hundreds of years of research in physics, that one vibrating force can alter the frequency of another. Metal tuning forks are a common, dramatic example: a tuning fork that has been struck will cause a nearby similar tuning fork that has not been struck to begin vibrating. They share a resonant, or a similar frequency. Sound waves moving through the air can literally cause an inert adjacent mass (of similar resonance) to begin vibrating. For example, a tuning fork may cause another fork to vibrate, but it would not cause a rock to vibrate because they do not share resonant frequencies. Ostad Elahi’s music is highly resonant and his method of playing was designed to use these principles to enrich the sounds of the tanbour.

Another important facet of resonance is entrainment. Resonance relates to tone, entrainment to rhythm. In the context of music and sound, entrainment may be viewed as the process whereby our major internal body systems speed up or slow down to match an external periodic rhythm. When we see someone tapping their foot or gingerly moving to music, they are responding—or entraining—to an external rhythm. Internally, a physical response is also taking place: brainwaves, heart rate, and respiration are speeding up or slowing down to match that ongoing rhythmic pulse.

Putting it all together, most auditory training is based upon tones (resonating organs, tissues, and bones) and external tempos (modulating our major pulse systems). Some pitches rev us up, while some tempos slow us down, and vice versa. Tones and rhythms are the raw material of organized sound, and that adds up to music! When music is improvised intentionally, tone and rhythm can turn into sound stimulation auditory training.

The purpose of this program is to improve your ability to perceive a full range of frequencies and to help you listen actively. Active listening improves tonal processing, and improved tonal processing by the ear and brain supports better auditory sequential processing and language processing.