Final answer:
The increase in loudness during voice production is due to the way sound waves are amplified in the resonant cavities of the throat and mouth, and modified by the positioning of the tongue. Differences in these cavities, like during male puberty, also lead to variations in pitch and timbre of the voice, differentiating individual voices and sounds.
Step-by-step explanation:
The perceptual increase in loudness of the laryngeal tone during voice production is indeed due to the concentration and reflection of sound waves by the oral, pharyngeal, and nasal cavities. As the air travels up from the lungs, it makes the vocal cords vibrate, creating sound waves that travel through the throat and mouth, which act as resonant cavities. These cavities amplify the sound by resonance. The tongue helps in adjusting the fundamental frequency and the combination of overtones, which are responsible for the uniqueness of each individual's voice.
During puberty in males, the growth of the larynx and changes in the shape of the resonant cavity alter the predominant frequencies of speech, contributing to the difference in vocal pitches between sexes. In addition, the loudness of a voice increases with the airflow from the lungs, which increases the amplitude of the sound pressure wave. The overall process results in variations of tone quality or timbre, which is why we can differentiate between different voices and sounds from various musical instruments.