Title

Voice and Laryngeal Design: The Role of Vocal Fold Architecture

Poster Number

24

Lead Author Major

Biological Sciences

Format

Poster Presentation

Faculty Mentor Name

Marcos Gridi-Papp

Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

The vibration of vocal folds is a complex phenomenon and it was first modeled with reasonable predictive power in the 1970's. Like mammals, frogs make sounds with a pair of vocal folds, but these have a different geometry, being highly concave upstream. Our previous measurements in frog larynges indicate that at the onset of sound, they function as reed-based wind instruments, where maximum airflow occurs at intermediate pressures. The purpose of this study is to design artificial larynges to test hypotheses and model aspects of sound production in frogs. A computer-controlled source of air was connected to a PVC pipe holding a pair of latex vocal folds configured to produce sound. Artificial laryngeal air pressure, airflow and generated sounds were recorded in an anechoic chamber. The vocal folds are positioned in two ways: a) the membranes are completely flat, or b) they have a thickened medial edge that makes them become concave upstream (like a parachute) as the driving air pressure is increased. Preliminary data show that with the reinforced medial edge, our artificial vocal folds vibrate within an extended range of pressures, with increased sound intensity and reduced airflow. This indicates that the reinforced medial edges lead to increased concavity of the membranes, producing a lateral force that compresses the medial edges against each other. This lateral force should be the key that allows the vocal folds of frogs to produce intense sound over a wide range of pressures without requiring muscular positioning of the vocal folds.

Location

Grave Covell

Start Date

21-4-2012 10:00 AM

End Date

21-4-2012 12:00 PM

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Apr 21st, 10:00 AM Apr 21st, 12:00 PM

Voice and Laryngeal Design: The Role of Vocal Fold Architecture

Grave Covell

The vibration of vocal folds is a complex phenomenon and it was first modeled with reasonable predictive power in the 1970's. Like mammals, frogs make sounds with a pair of vocal folds, but these have a different geometry, being highly concave upstream. Our previous measurements in frog larynges indicate that at the onset of sound, they function as reed-based wind instruments, where maximum airflow occurs at intermediate pressures. The purpose of this study is to design artificial larynges to test hypotheses and model aspects of sound production in frogs. A computer-controlled source of air was connected to a PVC pipe holding a pair of latex vocal folds configured to produce sound. Artificial laryngeal air pressure, airflow and generated sounds were recorded in an anechoic chamber. The vocal folds are positioned in two ways: a) the membranes are completely flat, or b) they have a thickened medial edge that makes them become concave upstream (like a parachute) as the driving air pressure is increased. Preliminary data show that with the reinforced medial edge, our artificial vocal folds vibrate within an extended range of pressures, with increased sound intensity and reduced airflow. This indicates that the reinforced medial edges lead to increased concavity of the membranes, producing a lateral force that compresses the medial edges against each other. This lateral force should be the key that allows the vocal folds of frogs to produce intense sound over a wide range of pressures without requiring muscular positioning of the vocal folds.