Equal loudness contours
DEFINITION
Curves represented in graph form as a function of sound level and frequency which listeners perceive as being equally loud. High frequency sounds above 2000 Hz are more annoying. Human hearing is less sensitive to low frequency sound. (See also PHON.)<br><br>A drawing of several curves showing how loud the tones of different frequencies would have to be played for a person to say they were of equal loudness.