However as knowledge of human physiology has increased over the past two hundred years, so has the understanding of the physical process of singing and vocal production. As a result, many vocal pedagogists have redefined or even abandoned the use of the term chest voice. In particular, the use of the term chest register has become controversial since vocal registration is more commonly seen today as a product of laryngeal function that is unrelated to the physiology of the chest and lungs. For this reason, many vocal pedagogists argue that it is meaningless to speak of registers being produced in the chest. The vibratory sensations which are felt in these areas are resonance phenomena and should be described in terms related to vocal resonance, not to registers. These vocal pedagogists prefer the term "chest voice" over the term "chest register". These vocal pedagogists also hold that many of the problems which people identify as register problems are really problems of resonance adjustment. This helps to explain the controversy over this terminology. Also, the term chest register is not used within speech pathology and is not one of the four main vocal registers identified by speech pathologists. For the purposes of this article, the term "chest voice" is adopted as it is less controversial.
The contemporary use of the term chest voice often refers to a specific kind of vocal coloration or vocal timbre. In classical singing, its use is limited entirely to the lower part of the modal register or normal voice. Chest timbre can add a wonderful array of sounds to a singers vocal interprettive palette. The introduction of chest timbre is common to singers trained in the historic Italian school, but largely shunned among singers who have emerged from the Nordic/Germanic tradition. Such approval or disapproval is largely an aesthetic decision. However, the use of overly strong chest voice in the higher registers in an attempt to hit higher notes in the chest can lead to forcing. Forcing can lead consequently to vocal deterioration.
This view understands chest voice as the vocal register used within normal speech. It was discovered via stroboscope that during ordinary phonation, or speaking in a man the vocal folds contact with each other completely during each vibration closing the gap between them fully, if just for a small length of time. This closure cuts off the escaping air. When the air pressure in the trachea rises as a result of this closure, the folds are blown apart, while the vocal processes of the arytenoid cartilages remain in apposition. This creates an oval shaped gap between the folds and some air escapes, lowering the pressure inside the trachea. Rhythmic repetition of this movement a certain number of times a second creates a pitched note. This is how the chest voice is created.
During singing in the lower register, the larynx is lowered since the muscles which connect it to the rib cage are tensed whereas the muscles above the larynx are not tensed. Consequently, a large proportion of the vibratory energy is transmitted to the thoracic area, giving singers the impression that their voice is resonating in the chest. This impression however is false. The chest by virtue of its design and location can make no significant contribution to the resonance system of the voice. The chest is on the wrong side of the vocal folds and there is nothing in the design of the lungs that could serve to reflect sound waves back toward the larynx.