Abstract
On the efficiency of vocalization in humans and other vertebrates
The Journal of the Acoustical Society of America, Vol.141(5 Supplement), pp.3875-3875
05/2017
DOI: 10.1121/1.4988665
Abstract
Human vocalization is an inefficient process in terms of energy expended to produce acoustic output. A traditional measure of vocal efficiency, the ratio of acoustic power radiated from the mouth to aerodynamic power produced by the lungs, ranges between 0.001 % and 0.1 % in speech-like vocalization. Non-human vertebrates like birds cannot afford to operate with such low efficiency when calling or singing over long distances. A hypothesis is given here that humans have traded away efficiency to maximize phonetic contrast in speech. A Navier-Stokes solution of non-steady compressible airflow from trachea to lips was used to calculate steady aerodynamic power, acoustic power, and combined total power at seven strategic locations along the airway. At low (speech-like) frequencies, it is shown that little power is radiated from the mouth because acoustic wave reflection at the mouth is very high. Wall vibration and kinetic pressure losses consume on the order of 99.99 % of the power produced. With higher frequency and greater mouth opening, the efficiency for calling, singing, or screaming can be increased by several orders of magnitude, approaching the efficiency of high intensity animal calls.
Details
- Title: Subtitle
- On the efficiency of vocalization in humans and other vertebrates
- Creators
- Ingo R. Titze - University of Utah
- Resource Type
- Abstract
- Publication Details
- The Journal of the Acoustical Society of America, Vol.141(5 Supplement), pp.3875-3875
- DOI
- 10.1121/1.4988665
- ISSN
- 0001-4966
- eISSN
- 1520-8524
- Number of pages
- 1
- Date published
- 05/2017
- Academic Unit
- Communication Sciences and Disorders; School of Music
- Record Identifier
- 9984719733702771
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