Singing is the act of producing musical sounds with the voice, and augments regular speech by the use of both tonality and rhythm. A person who sings is called a singer or vocalist. Singers perform music known as songs that can either be sung a cappella (without accompaniment) or accompanied by musicians and instruments ranging from a single instrumentalist to a full symphony orchestra or big band. Singing is often done in a group of other musicians, such as in a choir of singers with different voice ranges, or in an ensemble with instrumentalists, such as a rock group or baroque ensemble. Nearly anyone who can speak can sing, since in many respects singing is a form of sustained speech.
Singing can be informal and done for pleasure; for example, singing in the shower or karaoke; or it can be very formal, as in the case of singing during a religious ritual such as a Mass or professional singing typically done on stage or in a recording studio. Singing at a high amateur or professional level usually requires instruction, and regular practice. Professional singers usually build their careers around one specific musical genre, such as Classical or rock, and they typically take voice training provided by a voice teacher or vocal coach throughout their career.
In its physical aspect, singing has a well-defined technique that depends on the use of the lungs, which act as an air supply, or bellows; on the larynx, which acts as a reed or vibrator; on the chest and head cavities, which have the function of an amplifier, as the tube in a wind instrument; and on the tongue, which together with the palate, teeth, and lips articulate and impose consonants and vowels on the amplified sound. Though these four mechanisms function independently, they are nevertheless coordinated in the establishment of a vocal technique and are made to interact upon one another. During passive breathing, air is inhaled with the diaphragm while exhalation occurs without any effort. Exhalation may be aided by the abdominal, internal intercostal and lower pelvic muscles. Inhalation is aided by use of external intercostals, scalenes and sternocleidomastoid muscles. The pitch is altered with the vocal cords. With the lips closed, this is called humming.
The sound of each individual's singing voice is entirely unique not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body. Humans have vocal folds which can loosen, tighten, or change their thickness, and over which breath can be transferred at varying pressures. The shape of the chest and neck, the position of the tongue, and the tightness of otherwise unrelated muscles can be altered. Any one of these actions results in a change in pitch, volume, timbre, or tone of the sound produced. Sound also resonates within different parts of the body, and an individual's size and bone structure can affect the sound produced by an individual.
Singers can also learn to project sound in certain ways so that it resonates better within their vocal tract. This is known as vocal resonation. Another major influence on vocal sound and production is the function of the larynx which people can manipulate in different ways to produce different sounds. These different kinds of laryngeal function are described as different kinds of vocal registers. The primary method for singers to accomplish this is through the use of the Singer's Formant; which has been shown to match particularly well to the most sensitive part of the ear's frequency range.
Vocal registration refers to the system of vocal registers within the human voice. A register in the human voice is a particular series of tones, produced in the same vibratory pattern of the vocal folds, and possessing the same quality. Registers originate in laryngeal function. They occur because the vocal folds are capable of producing several different vibratory patterns. Each of these vibratory patterns appears within a particular range of pitches and produces certain characteristic sounds. The term "register" can be somewhat confusing as it encompasses several aspects of the human voice. The term register can be used to refer to any of the following:
In linguistics, a register language is a language which combines tone and vowel phonation into a single phonological system. Within speech pathology the term vocal register has three constituent elements: a certain vibratory pattern of the vocal folds, a certain series of pitches, and a certain type of sound. Speech pathologists identify four vocal registers based on the physiology of laryngeal function: the vocal fry register, the modal register, the falsetto register, and the whistle register. This view is also adopted by many vocal pedagogists.
Vocal resonation is the process by which the basic product of phonation is enhanced in timbre and/or intensity by the air-filled cavities through which it passes on its way to the outside air. Various terms related to the resonation process include amplification, enrichment, enlargement, improvement, intensification, and prolongation, although in strictly scientific usage acoustic authorities would question most of them. The main point to be drawn from these terms by a singer or speaker is that the end result of resonation is, or should be, to make a better sound. There are seven areas that may be listed as possible vocal resonators. In sequence from the lowest within the body to the highest, these areas are the chest, the tracheal tree, the larynx itself, the pharynx, the oral cavity, the nasal cavity, and the sinuses.