Sound in the audible band, sound outside the audible band.

Audible frequency band means the frequency band of sound that humans can perceive. When converted into hertz (Hz), it is about 20Hz to 20000Hz. Sounds that are higher than the audible frequency band (sounds with a frequency of 20000 Hz or higher) are called “high frequency”, and sounds that are lower than the audible frequency band are called “low frequency”. 

Voices that people usually utter in everyday conversation are between 250Hz and 4,000Hz, of which male voices around 500Hz and female voices around 1,000Hz. Human hearing is said to be most sensitive around 3,000Hz, and voices and sounds that should be noticed for sure by humans, such as baby's cry, women's scream, voice calling out to someone in the distance and warning sound of home appliance, are said to be around 2,000Hz to 4,000Hz.




On the positive effects of high-frequency sound on humans

The upper limit of the human audible frequency band is thought to be 20,000 Hz, and sound waves with frequencies higher than that, have not been regarded as “sound” for a long time because they cannot be heard by the human ear. However, it has been made clear in recent years that such high-frequency sounds are transmitted from the skin to the brain.


Akikazu Nakamura, a composer and shakuhachi (bamboo clarinet) player, states the following in his book “Harmonic Tone:A cultural Note of Sound, Language and Body” (see pp.32-34).


“Sounds above 20,000 Hz, or high-frequency sounds, are transmitted through the skin to the brain. Then, that sound increases blood flow in the thalamus and activates the fundamental brain(the diencephalon and mesencephalon). From this fact, we could infer as following about Japanese clothes, namely while today’s Western style clothes which cover the entire body, inevitably block high-frequency, Japanese clothes which have open collars, cuffs and hem, make the skin open to the atmosphere, and therefore, make it possible to take in high-frequency components into the body without cutting them off.”



<Effect of high frequency transmitted from the skin to the brain>


◎Alpha waves increase.


NK cells (natural killer cells) increase.

 →Cancer is suppressed.


Immunoglobulin A increases.

 →Immune function-enhancing hormones increase.

Chromogranin A increases.

 →Stress is decreased by increase of anti-stress hormones.


Adrenaline decreases.

 →Fight or flight reaction decreases.

 →Feeling is stabilized and relaxed.



Even if there is only high-frequency sound, there is no effect. Its positive effect appears only when both the audible band and the high-frequency component beyond the audible band are sounding together.



Akikazu Nakamura, Harmonic Tone:A cultural Note of Sound, Language and Body, Shunjusha, November 1, 2010.

Tsutomu Ohashi, Hypersonic effect, Iwanamishoten, September 23, 2017.








作曲家で尺八奏者の中村明一氏は、著書「倍音 音・言葉・身体の文化誌」p.32-34で、以下のように述べています。









倍音 音・ことば・身体の文化誌