Outer and middle ear damage changes the loudness frequency balance

Evidence

There are many practical implications for equal-loudness contours. First, the data above suggest that the loudness of sounds across frequency is predominantly determined by the characteristics of the outer and middle ear. Disorders in these structures will alter the relationship between the loudness of sounds across frequency. Second, equal-loudness contours have many practical implications and are used in the design of alarms and sirens and in numerous audio production applications. Further, the A-weighted decibel (dB A) uses the 40-phon loudness contour to calculate a decibel metric that is more similar to the sound level as represented by the human ear. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 754

Categorization

• DEFINE: Introduces dB A weighting as built on the 40-phon contour; key applied metric.
• XREF: dB A weighting connects directly to the noise-exposure and industrial dosimetry topic from the One Square Inch silence reading.