(from the article `ultrasonics`) ...to the ears of people working nearby. This type of device is often used in offices of doctors and other professionals. Another technique for ...
Found on
http://www.britannica.com/eb/a-z/h/28
device placed within the external ear canal, in the concha, over the ear, or over a substantial part of the head to protect the hearing organ from noise
Found on
http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=801-28-21
Personal device worn to reduce harmful auditory or annoying subjective effects of sound.Equal-Energy HypothesisA hypothesis stating that equal amounts of sound energy will produce equal amounts of hearing impairment, regardless of how the sound energy is distributed in time.
Found on
https://www.encyclo.co.uk/local/20687
No exact match found.
