From WebRef.org
Jump to: navigation, search

A contour representing a constant loudness for all audible frequencies. The contour having a sound pressure level of 40 dB at 1000 Hz is arbitrarily defined as the 40-phon contour.

Sponsor: Suffer from foot pain? Plantar Fasciitis? Metatarsalgia or heel spurs? Happy Feet Plus has specialized in relieving your pain since 1985!