Noise Measurement

The instrumental measurement of noise presents difficulties that have in the past generally defeated its successful accomplishment. While noise exists in a physical state and certain of its quantities are susceptible to direct measurement, the magnitude of a noise is evaluated through the interpretation of the human ear. The ear is non-linear in its evaluation of the various factors of noise. The degree and nature of the ear's non-linearity to the principal factors is discussed, with respect to the chief interpretative impression, that of loudness. — Audiometric measurements approached a more proper evaluation of noise, but in addition to dependency upon human judgment, were only approximate, and represented comparisons of physiological effects of noise rather than true noise values. — An instrument is described that measures intensity expressed in terms of loudness, evaluated for frequency and duration, and which combines portions of a complex waveshape in a suitable manner. The characteristics of the meter and the ear are compared. The readings are in decibels above a zero reference point near the threshold of audibility. The selection and meaning of this scale is explained. Where it is desired to analyze the pitch or frequency of a noise, an analyzer attachment permits either band or single-frequency analysis. Some limitations in its use in making noise measurements are discussed.

Print ISSN

0097-5834

Published

1931-12

Content type

Original Research

DOI

10.5594/J07489