Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech Purpose Sound pressure level (SPL) measurement of voice and speech is often considered a trivial matter, but the measured levels are often reported incorrectly or incompletely, making them difficult to compare among various studies. This article aims at explaining the fundamental principles behind these measurements and providing guidelines to improve ... Tutorial
Tutorial  |   March 15, 2018
Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech
 
Author Affiliations & Notes
  • Jan G. Švec
    Department of Biophysics, Faculty of Science, Palacký University, Olomouc, Czech Republic
  • Svante Granqvist
    Department of Basic Science and Biomedicine, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
    Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Jan G. Švec: jan.svec@upol.cz
  • Editor-in-Chief: Julie Liss
    Editor-in-Chief: Julie Liss×
  • Editor: Jack Jiang
    Editor: Jack Jiang×
Article Information
Hearing & Speech Perception / Acoustics / Special Populations / Genetic & Congenital Disorders / Speech, Voice & Prosody / Speech / Tutorial
Tutorial   |   March 15, 2018
Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 441-461. doi:10.1044/2017_JSLHR-S-17-0095
History: Received March 9, 2017 , Revised July 10, 2017 , Accepted August 16, 2017
 
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 441-461. doi:10.1044/2017_JSLHR-S-17-0095
History: Received March 9, 2017; Revised July 10, 2017; Accepted August 16, 2017
Web of Science® Times Cited: 2

Purpose Sound pressure level (SPL) measurement of voice and speech is often considered a trivial matter, but the measured levels are often reported incorrectly or incompletely, making them difficult to compare among various studies. This article aims at explaining the fundamental principles behind these measurements and providing guidelines to improve their accuracy and reproducibility.

Method Basic information is put together from standards, technical, voice and speech literature, and practical experience of the authors and is explained for nontechnical readers.

Results Variation of SPL with distance, sound level meters and their accuracy, frequency and time weightings, and background noise topics are reviewed. Several calibration procedures for SPL measurements are described for stand-mounted and head-mounted microphones.

Conclusions SPL of voice and speech should be reported together with the mouth-to-microphone distance so that the levels can be related to vocal power. Sound level measurement settings (i.e., frequency weighting and time weighting/averaging) should always be specified. Classified sound level meters should be used to assure measurement accuracy. Head-mounted microphones placed at the proximity of the mouth improve signal-to-noise ratio and can be taken advantage of for voice SPL measurements when calibrated. Background noise levels should be reported besides the sound levels of voice and speech.

Acknowledgments
This work was supported by the Czech Science Foundation (GA CR) Project GA16-01246S, awarded to Jan G. Švec, and by Svante Granqvist. Supplemental material to this article in the form of MATLAB scripts is available at http://www.mathworks.com/matlabcentral/fileexchange/64231-calibratevoicespl.
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