The Ear's Response Curve

Author: N.H. Crowhurst

To make these basic hearing tests, a number of people were used as subjects. Each person was asked to tell when tones of different frequency sounded equally loud. Using a frequency of 1000 cycles as a reference, the response of individual ears could be plotted in this way for different volume levels. When this was done, an average was taken for a large number of people, and the resulting curves are shown here. These curves are not a close representation of the response of your ears, nor indeed of any one person's. Careful analysis of the results showed that hardly anyone has an "average" pair of ears. Individual hearing may differ widely (by 10 decibels or more) from the average response.

Equal loudness curves

This fact shows us that "taste" in music or quality is not solely responsible for differences in opinion about audio equipment - individual people's ears give different impressions for them to judge by. Added to this difference is the fact that we do not hear a musical program as a number of groups of frequencies. In the composite of frequencies presented, our ears have the ability to recognize individual instruments in an orchestra (if the reproduction is good) even though the frequencies each instrument uses overlap.

These facts can readily be recognized by anyone with a little listening experience. They are mentioned here to complete the picture of what comprises "Audio".