The sound’s pitch is made in the vocal cords, and its tone is made in the five resonance chambers. The 5 chambers are as follows:
➀The laryngeal ventricle between the vocal fold and the vestibular fold (false vocal cord )
➁The piriform recess (the space between the vestibular fold and the epiglottis)
➂The pharyngeal cavity (at the back of the hyoid bone)
➃The oral cavity in the mouth
➄The nasal cavity in the nose (Figure1)
The pharyngeal cavity(➂) is absolutely the most important for vocalization.
The pharyngeal cavity’s space can change by moving the hyoid bone. The shape and hardness of the soft tissue can be also be changed, depending on how much or little activity/muscle training around the pharyngeal cavity.
The hyoid bone is suspended by the stylopharyngeus muscle and the stylohyoid muscle is in the air. (Figure2)
Furthermore, the muscles attaching to the hyoid bone are the : middle constrictor, the genioglossus muscle, the mylohyoid muscle, the hyoglossus muscle, the sternohyoid muscle, the thyrohyoid muscle, and the omohyoid muscle.
These muscles contract to fix the hyoid bone’s placement, and the voice is changed. This vocal change degree is determined by how smooth and precise that muscle group moves.
Note1:When comparing production of a human voice to a guitar, imagine the vocal chords are the strings and the pharyngeal cavity is the body of the instrument. The sound is made by the strings and is resonated in the body.
Note2:The words are made in the oral cavity, using mouth and tongue movements, and the sound tone is made in the nasal cavity.
Although the nasal cavity is a very small space, similar to a guitar it plays a vital part, which is to change the voice tones from vibrating air.