hearing level

Hearing level is the sound pressure level produced by an audiometer at a specific frequency. It is measured in decibels with reference to audiometric zero.{{cite web|title=The Audiogram|url=http://www.vanasch.school.nz/pdfs/audiogram.pdf|publisher=VanAsh Deaf Education Center|accessdate=16 December 2012|archive-url=https://web.archive.org/web/20120227050639/http://www.vanasch.school.nz/pdfs/audiogram.pdf|archive-date=27 February 2012|url-status=dead}} Hearing of speech is considered to be impaired when the hearing level is shifted 25 dB or more.{{cite web|last=Truax|first=Barry|title=Hearing level|url=https://www.sfu.ca/sonic-studio/handbook/Hearing_Level.html|work=Handbook for acoustic ecology|publisher=SFA|accessdate=16 December 2012|archive-url=https://web.archive.org/web/20121128200804/http://www.sfu.ca/sonic-studio/handbook/Hearing_Level.html|archive-date=28 November 2012|url-status=dead}}