In humans, singers often open their mouths as wide as possible to produce powerful high tones. This happens because the vocal tract, acting as a tube resonator, can adopt specific shapes to better project certain pitches and resonance overtones. In non-human primates, this ability of “tuning” the vocal tract to certain frequencies was never quantitatively investigated. The song is a vocal display in which indris emit a sequence of calls separated by pauses. It probably serves as a territorial announcement and defence. For the purpose of this study, we recorded the songs of the indris (Indri indri) in Madagascar. A total of 70 songs were audio-recorded from 35 indris, both sexes, between 2004 and 2006. Additional video recordings were taken to allow description of vocal production mechanisms, including mandibular manoeuvres and lip movements. 926 non-overlapping notes were analyzed using Praat to collect fundamental frequency (F0) parameters and formants. Mouth opening was significantly correlated with average fundamental frequency and first formants. Computational models of the vocal tract provided evidence that different vocal tract configurations possess different resonances and that slight changes of F0 would allow a better projection of the vocal signal.

Singers in the forest: acoustic structure of indri’s loud calls and vocal tract tuning in a prosimian primate

FAVARO, LIVIO;GAMBA, Marco;SORRENTINO, VIVIANA;TORTI, VALERIA;GIACOMA, Cristina
2008

Abstract

In humans, singers often open their mouths as wide as possible to produce powerful high tones. This happens because the vocal tract, acting as a tube resonator, can adopt specific shapes to better project certain pitches and resonance overtones. In non-human primates, this ability of “tuning” the vocal tract to certain frequencies was never quantitatively investigated. The song is a vocal display in which indris emit a sequence of calls separated by pauses. It probably serves as a territorial announcement and defence. For the purpose of this study, we recorded the songs of the indris (Indri indri) in Madagascar. A total of 70 songs were audio-recorded from 35 indris, both sexes, between 2004 and 2006. Additional video recordings were taken to allow description of vocal production mechanisms, including mandibular manoeuvres and lip movements. 926 non-overlapping notes were analyzed using Praat to collect fundamental frequency (F0) parameters and formants. Mouth opening was significantly correlated with average fundamental frequency and first formants. Computational models of the vocal tract provided evidence that different vocal tract configurations possess different resonances and that slight changes of F0 would allow a better projection of the vocal signal.
35° Convegno Associazione Italiana di Acustica
Milano
11-13 Giugno 2008
32
35
35
Favaro L.; Gamba M.; Sorrentino V.; Torti V.; Giacoma C.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/74045
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