Chest voice and head voice. Myth or fact?
Chest voice and head voice are ancient terms that go back hundreds of years when there was little understanding of how the voice works. Without knowing the facts of sound production, description of the voice relied solely upon the sound and physical sensations that singers heard and felt when they sang.
We now know that the sensation of sound being generated or placed either in the chest or head arises from sympathetic vibrations, from bone conduction or muscular effort. The sound production mechanism doesn’t change position – the sound stems from the vibration of the vocal folds, which are housed in the larynx. It is essential to understand this phenomenon and the fact that different pitches and vowels will give a feeling of sympathetic vibration in various places in our bodies.
It is more accurate to refer to the head and chest registers. A vocal register is usually different in vocal acoustic characteristics and muscular adjustment of the vocal folds and may be associated with different parts of your range. These adjustments are primarily controlled by the TA (thyroarytenoids muscles) and the CT (cricothyroids). The TA are muscles that make up the body of the vocal folds and are responsible for vocal fold shortening. The CTs are thinning muscles that lie partly outside the larynx and are responsible for vocal fold stretching.
Therefore, we call a sound ‘chestier’ if shorter, thicker, looser folds vibrate at lower frequencies (number of vibrations per second). Following the same principle, a sound is ‘headier’ if longer, thinner folds vibrate at higher frequencies. These different modes of vibration are called laryngeal mechanisms. Although flexible, the vocal folds have physical limitations and they might slip from one mode to another at certain pitches (called vocal breaks).
As for the mixed voice, it is a controversial concept. There is actually no separate register for mix, and there are no new muscles involved in its production. What this term usually means is an area of cooperation between the TAs and CTs that indicates a subtle timbral distinction (from chest and head registers) and a less heavy production. In other words, the mix is a blend of the two registers and is obtained by training muscle coordination and employing specific acoustic strategies. The goal is to master singing in the vocal break area between chest and head without a sudden change in sound quality.