Physiologic and acoustic differences between male and female voices

Area of Science:

• Laryngeal anatomy and physiology
• Acoustic phonetics
• Bioacoustics

Background:

• Significant anatomical and physiological differences exist between male and female larynges.
• These differences are known to influence vocal characteristics such as fundamental frequency and sound production.

Purpose of the Study:

• To compare male and female larynges based on size, vocal fold length, tissue elasticity, and glottal shape.
• To propose scale factors that explain observed sex differences in voice production parameters.
• To investigate glottographic waveform differences using computer modeling of vocal fold contact area.

Main Methods:

• Comparative analysis of male and female laryngeal anatomy.
• Development of two scale factors to explain variations in voice parameters.
• Computer modeling (simulation) of vocal fold contact area to analyze glottal shape.

Main Results:

• Fundamental frequency is primarily scaled by vocal fold membranous length (scale factor 1.6).
• Mean airflow, sound power, and glottal efficiency are influenced by overall larynx size (scale factor 1.2).
• Computer models show a more linear convergence of the female glottis compared to the male glottis due to vocal fold bulging.

Conclusions:

• Laryngeal size and vocal fold length are key determinants of sex-based differences in voice production.
• The proposed scale factors provide a quantitative framework for understanding these differences.
• Vocal fold morphology significantly impacts glottal shape and contributes to distinct glottographic waveforms in males and females.