TITLE:
Loudness Summation and Weightings for Loudness and Environmental Noise Assessment
AUTHORS:
Juhani Parmanen
KEYWORDS:
Loudness, Loudness Level, Loudness Summation, Frequency Weightings, A-Weighting, Low Frequency Noise
JOURNAL NAME:
Open Journal of Acoustics,
Vol.4 No.3,
August
19,
2014
ABSTRACT: A stationary loudness model has been built up on the basis of the former
ISO 226: 1987 concerning equal-loudness-level contours. The loudness and
loudness level expressions derived in the study include the same parameters as
used when determining the equal-loudness-level contours of the former ISO
standard. However, as an additional main idea, a loudness summation rule has
been proposed in the study. Moreover, the loudness expressions have been
normalised to give the same values for people who have a similar sense of
hearing. It has also been found that the loudness expressions include basically
two different weightings. The first weighting is a conservative frequency
weighting in the domain of sound pressure level, and the second weighting
consists of coefficients applied to the weighted sound pressure levels. The
latter have the greatest effect on the very low-frequency range. Finally, the
paper includes a new way to use the A-weighting which takes into account the
compressed character of the equal-loudness-level contours at the low frequency
range. This method remarkably transforms the character of the A-weighting as a
measure for low-frequency environmental noise.