Effects of signal processing on the measurement of maximum sound pressure levels

Robinson, M and Hopkins, C ORCID: 0000-0002-9716-0793 (2014) Effects of signal processing on the measurement of maximum sound pressure levels. APPLIED ACOUSTICS, 77. pp. 11-19.

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Abstract

Maximum sound pressure levels are commonly used for environmental noise and building acoustics measurements. This paper investigates the signal processing errors due to Fast or Slow time-weighting detectors when combined with octave band filters, one-third octave band filters or an A-weighting filter. For 6th order Butterworth CPB filters the inherent time delay caused by the phase response of filters is quantified using three different approaches to establish the following rules-of-thumb: (1) time-to-gradient/amplitude matching occurs when Bt ≈ 1, (2) time-to-peak matching occurs when Bt ≈ 2 and (3) time-to-settle matching occurs when Bt ≈ 4 for octave band filters, and when Bt ≈ 3 for one-third octave band filters. Four different commercially- available sound level meters are used to quantify the variation in measured maximum levels using tone bursts, half-sine pulses, ramped noise and recorded transients. Tone bursts indicate that Slow time-weighting is inappropriate for maximum level measurements due to the large bias error. The results also show that there is more variation between sound level meters when considering Fast time-weighted maximum levels in octave bands or one-third octave bands than with A-weighted levels. To reduce the variation between measurements with different sound level meters, it is proposed that limits could be prescribed on the phase response for CPB filters and A-weighting filters. © 2013 Elsevier Ltd. All rights reserved.

Item Type:	Article
Additional Information:	Open Access funded by Engineering and Physical Sciences Research Council Under a Creative Commons license (http://creativecommons.org/licenses/by/3.0/)
Uncontrolled Keywords:	Maximum sound pressure level, Signal processing, Sound level meter, Transient, Impulse
Subjects:	?? T1 ?? ?? TJ ??
Depositing User:	Symplectic Admin
Date Deposited:	09 Dec 2015 15:44
Last Modified:	16 Dec 2022 12:11
DOI:	10.1016/j.apacoust.2013.09.017
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2041901

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