Acoustic, Aerodynamic, and Kinematic Description of “Taan” Gestures in Indian Classical Singing

Nandhakumar Radhakrishnan & Ronald C. Scherer,
200, Student Health Center, Dept. CDIS, Bowling Green State University,
Bowling Green, Ohio, USA 43402.
Email: nandhak@bgnet.bgsu.edu, ronalds@bgnet.bgsu.edu, Ph: 419-372-7189

Introduction:
The two major divisions in Indian classical music, the North Indian, or Hindustani, and South Indian, or Carnatic, require extensive training and are considered sacred. We studied the vocal physiology of an Indian classical singer during “taan” production, an important aspect of ornamentation (like vibrato, trill, and trillo) in the North Indian style of vocal music. Taan is a melodic embellishment consisting of asymmetric rapid pitch rise and fall, the rate of which can be varied by the singer.

Methodology:
• A 44 year old male, well-known Hindustani professional classical singer was the subject. Acoustic, kinematic (EGG), and airflow signals were recorded when the singer produced taan gestures while seated in a sound treated booth.
• Each local rise then fall of the Fo contour was defined as a “taan gesture.” A series of taan gestures was produced during constant pitch and during an octave increase and decrease.

Results and Discussion:
a. Taan produced while singing a constant pitch:
(i) Acoustic: Average frequency extent: 1.87 ST (0.34 SD). Average frequency rate: 3.41
Hz (0.36 Hz SD).

(ii) Kinematic: Within-taan frequency increase resulted in an increase in EGGW (i.e.,
greater adduction for higher frequencies.)

(iii) Airflow: For most of the taan gestures, the AC flow decreased with increase in pitch.
OQ decreased with an increase in frequency.

b. Taan produced while singing octaves:
(i) Acoustic: On average, the number of semitones on the ascending side of the octave-up of each taan gesture was 4.00 semitones, and 1.55 semitones on the descending side. On the octave-down side there were 3.31 and 1.94 semitones on the descending and ascending sides, respectively. Within the taan gestures, when the frequency was lower-higher-lower, the intensity was usually higher-lower-higher, an inverse relationship.

(ii) Kinematic: EGGW adduction measures increased with within-taan pitch rise,
suggesting an increase in vocal fold adduction.

(iii) Airflow: The glottal AC flow measures did not indicate a trend with pitch.

(iv) DC shifting: Based on the DC shifting behavior of the flow waveform, the larynx
was estimated to rise and fall by approximately 1 cm.

Conclusion:
“Taan gestures” by the professional singer-subject appears to be characterized by control via glottal adduction and wide pitch fluctuations. The asymmetric frequency modulation appears to be controlled voluntarily, unlike vibrato. The rate of taan of 3.41 Hz is slower than vibrato, trillo, or trill. The extent of 1.89 ST is wider than vibrato but similar to trillo and trill. During taan, this subject appeared to increase and maintain a relatively high glottal adduction, perhaps to maintain a consistent timbre. The AC flow varied with Fo for the taan gestures produced while singing a “constant pitch”, but did not vary with Fo for the octave scales. It is hypothesized that a continuous change in laryngeal height (a 1 cm rise and fall) created a pumping action of the flow and contributed to the DC shift of flow and the modulated EGG waveform during the octave scales.

Averages from literature and current study

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