The vocal fry register (also known as pulse register, laryngealization, pulse phonation, creak, croak, popcorning, glottal fry, glottal rattle, glottal scrape, or strohbass) is the lowest vocal register and is produced through a loose glottal closure which will permit air to bubble through slowly with a popping or rattling sound of a very low frequency. During this phonation, the arytenoid cartilages in the larynx are drawn together which causes the vocal folds to compress rather tightly and become relatively slack and compact. This process forms a large and irregularly vibrating mass within the vocal folds that produces the characteristic low popping or rattling sound when air passes through the glottal closure. The register (if well controlled) can extend far below the modal voice register, in some cases up to 8 octaves lower, such as in the case of Tim Storms who holds the world record for lowest frequency note ever produced by a human, a G−7, which is only 0.189 Hz. Humans however can only hear sounds down to 12 Hz under ideal conditions.
History of register classification
The vocal fry register has been a recognized and identifiable register in American English only within the past few decades, but its characteristic sound was recognized much earlier. Discussion of the vocal fry or pulse register began first within the field of phonetics and speech therapy and did not enter the vocabulary of vocal music pedagogists until the early 1970s, when it was initially controversial. However, the controversy surrounding the term within vocal music has subsided as more research into the use of the vocal fry register within the context of singing ensued. In particular, vocal pedagogist Margaret Greene's videotaping of the physiological processes occurring in the body while singers were phonating in the vocal fry register offered solid evidence that this type of vocal phonation should be considered a vocal register within both a speech pathology and vocal music perspective. As with any other vocal register, the vocal fry register has a unique vibratory pattern of the vocal folds, a certain series of pitches, and a certain type of sound that distinguishes it from other vocal registers.
Some researchers have argued that vocal fry is a register in American English used by girls and women to give their voice more credibility, while others argue that the result is that they sound less confident, undermining the effectiveness of their communication. Time reports that it hampers job interviews. Others argue that these perceptions are part of a broader attack on women's speech. Although the phenomenon of vocal fry is not limited to women its use is more prevalent in women than in men. When asked to read a passage, female speakers used vocal fry at a rate four times higher than male speakers. Vocal fry is generally seen as a negative characteristic in the workplace, but a study by Duke University researchers has determined this phenomenon is becoming more common and socially acceptable.
Discussion of vocal fry is much more frequent in books related to phonetics and speech therapy than it is in those dealing with singing. Some authorities consider the use of vocal fry in speech a dysphonia, while others consider it so only if it is used excessively. Hollien, Moore, Wendahl, and Michel make this statement:
It is simply our intent to suggest that ordinarily vocal fry constitutes one of several physiologically available types of voice production on the frequency-pitch continuum and hence, of itself, is not logically classified among the laryngeal pathologies. While the excessive use of fry could result in a diagnosis of voice disorder, this quality is too often heard in normal voices (especially in descending inflections where the voice fundamentally falls below frequencies in the modal register) to be exclusively a disorder."
This seems to be the prevailing opinion among speech pathologists today. Many are quick to point out that although vocal fry is minimally a part of routine speaking patterns, the continued use of such a pattern does not make it utilitarian nor non-pathological.
Some evidence exists of vocal fry becoming more common in the speech of young female speakers of American English in the early 21st century, but the extent and significance of this are disputed. Researcher Ikuko Patricia Yuasa suggests that this tendency is a product of young women endeavoring to infuse their speech with gravitas by means of reaching for the male register and found that "college-age Americans [...] perceive female creaky voice as hesitant, nonaggressive, and informal but also educated, urban-oriented, and upwardly mobile".
Some languages, such as Jalapa Mazatec, use vocal fry (creaky voice) as a linguistically significant marker; that is, the presence or absence of vocal fry can change the meaning of a word.
A 2014 national study of American adults found that speech with vocal fry was perceived more negatively than a voice without vocal fry, particularly in a labor market context. In young adult women, it was perceived as sounding less trustworthy, less competent, less attractive and less hirable. This negative evaluation was stronger when the evaluator was also a woman.
The national study of 800 listeners across age groups found that people making hiring decisions preferred a voice without vocal fry to one with vocal fry. A limitation of the study was that the vocal fry samples were produced by imitators rather than natural vocal fry speakers. This suggests more research is needed, as the negative reaction could be attributable to other factors.
The croaking sound produced by male singers at the start of phrases in American country music is produced by moving from this to the modal register. Within choral music, when true basses are not available, choirs often rely on singers who can "fry" the low bass notes. Singers such as Tim Storms, Mike Holcomb and various other gospel basses use this technique to sing very low tones. Women are not usually required to sing in the vocal fry register, but some are capable of doing so. Some styles of folk singing, however, use the vocal fry register in the female voice. Vocal fry is also used in metal music, usually in combination with air from the diaphragm, in order to create a "growl" or "scream," which sounds aggressive and harsh.
The chief use of the vocal fry register in singing is to obtain pitches of very low frequency, which are not available to the singer in the modal register. Although the physiological production of the vocal fry register may be extended up into the modal register, most vocal pedagogues discourage such practices, as it may cause damage to the vocal cords. Also, many voice teachers discourage singers from using the vocal fry register frequently, as it may cause the singer to lose some of the upper notes in the modal register. In some cases, vocal pedagogues have found the use of vocal fry therapeutically helpful to students who have trouble producing lower notes. Singers often lose their low notes or never learn to produce them because of the excessive tension of the laryngeal muscles and of the support mechanism that leads to too much breath pressure.
Some overtone singing styles such as kargyraa use vocal techniques similar to vocal fry.