Expert: Harriet B Jacobster, Au.D. - 4/17/2008

Question
QUESTION: Hi:

Does the human hearing range really extend up to 100 kHz?

According to the site below, the answer is yes:

http://www.cco.caltech.edu/%7eboyk/spectra/spectra.htm

Is that website correct? Can the human auditory system actually detect frequencies as high as 100 kHz?


Thanks,

Green

ANSWER: Green,
The range of human hearing is 20 Hz to 20,000 Hz.  Any sound higher is called ultrasound and outside the range of human hearing.

Harriet B. Jacobster, AuD
Board Certified Doctor of Audiology

---------- FOLLOW-UP ----------

QUESTION: But does ultrasound have any effect on the human auditory system?

I'm just curious as to whether that website's information is true or just crackpot science?

It's also important to note that while sounds above 20 kHz may not be consciously perceived, they might have subtle effects on audio that would significantly affect the mood of the individual listening to music.

Answer
I cannot say whether it's true, but there is the possibility.  Since ultrasounds do produce vibrations, it may not be so far-fetched to imagine that something in our body would respond to these vibrations. Even the author admitted that further investigation is needed.  So, although I would not call it completely "true," I would not yet judge it as "crackpot science." I will have to say, though, that this is really my opinion based on my knowledge of physiology and acoustics.  There is a great resource that may have a better answer for you.  A great deal of research on auditory science is being done at McGill University in Canada.  Here is the link to the archives: http://lists.mcgill.ca/archives/auditory.html.  You might find the answer there.  Or you may check the McGill website and find a link to the auditory research department itself and ask them: http://www.mcgill.ca/.

Good luck.

Harriet B. Jacobster, AuD
Board Certified Doctor of Audiology