Sensitivity analysis of muscle mechanics-based voice simulator to determine gender-specific speech characteristics.

The purpose of this study was to investigate the gender differences in voice simulation using a sensitivity analysis approach. A global, Monte Carlo-based approach was employed, and the relationships between biomechanical inputs (lung pressure and muscle activation levels) and acoustic outputs (fundamental frequency, f, and sound pressure level, SPL) were investigated for male and female versions of a voice simulator model. The gender distinction in the model was based on an anatomical scaling of the laryngeal structures. Results showed strong relationships for f and SPL as functions of lung pressure, as well as for f as a function of cricothyroid and thyroarytenoid muscle activity, in agreement with previous literature. Also expected was a systematic shift in f range between the genders. It was found that the female model exhibited greater pitch strength (saliency) than the male model, which might equate to a perceptually more periodic or higher-quality voice for females. In addition, the female model required slightly higher lung pressures than the male model to achieve the same SPL, suggesting a possibly greater phonatory effort and predisposition for fatigue in the female voice. The methods and results of this study lay the groundwork for a complete mapping of simulator sound signal characteristics as a function of simulator input parameters and a better understanding of gender-specific voice production and vocal health.