15th International Congress of Phonetic Sciences (ICPhS-15)Barcelona, Spain |
Temporal periodicity is the main physical correlate used experimentally
in relating perceived pitch to vocal fold frequency. The accuracy of
most measurement methods does not, however, match the pitch difference
limens of normal hearing.
The experimental results presented here
are concerned with the observations, and resulting understanding, that
can be derived when routine analyses correspond to a 0.1% level of
frequency difference detection at 1kHz.
Three experimental situations
are briefly discussed. The first two concern the relation between sustained
vowel production and the modal structures found in the analysis of
representative samples of voice in connected speech for two groups
of subjects. Two of the main factors that contribute to our ability
to control voice pitch come from auditory processing and proprioceptive
laryngeal feedback. The analysis of representative samples of fluent
speech makes it possible to define the main modal values of vocal fold
vibration available to a speaker. In order to maintain pitch stability
in a sustained sound we have found that the normal speaker chooses
a dominant normal modal value of vocal fold vibration - defined from
within the characteristics of connected speech. The normally hearing
speaker but with a pathological voice adopts a related strategy. However,
for such speakers the choice of dominant mode may lead to stably controlled
voice pitch but at a quite abnormal vibratory frequency. These results
have practical implications in the clinical management of voice pathology
since it is not present practice to relate estimates of degree of pathology
derived from sustained vowels to measurement of connected speech. The
third set of related experiments concern the links between singing
and auditory monitoring. There is an inverse relation between our ability
to detect pitch change and the duration of the sound. This leads to
an approximately tenfold difference between detectable pitch changes
in sung vowels and the intonational changes of conversational speech.
Crossplot [period by period] analyses of voice frequency irregularity
in speech and singing lead, in consequence, to large predictable differences
between these modalities of production.
Bibliographic reference. Fourcin, Adrian / DeJong, Gea (2003): "Precision voice analysis in speaking, singing and pathology", In ICPhS-15, 2365-2368.