Analysis and Categorization of Various Types of Vocal Distortion in Rock, Metal, Pop Styles, and Throat Singing Observed by High-Speed Digital Imaging

Yogaku Lee; Masato Tanaka; Hikari Kato; Takashi Nakagawa; Satoshi Ishikawa; Tokihiko Kaburagi

doi:10.1016/j.jvoice.2024.11.041

Analysis and Categorization of Various Types of Vocal Distortion in Rock, Metal, Pop Styles, and Throat Singing Observed by High-Speed Digital Imaging

J Voice. 2025 Jan 8:S0892-1997(24)00424-7. doi: 10.1016/j.jvoice.2024.11.041. Online ahead of print.

Authors

Yogaku Lee¹, Masato Tanaka², Hikari Kato², Takashi Nakagawa³, Satoshi Ishikawa⁴, Tokihiko Kaburagi⁵

Affiliations

¹ Graduate School of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka 815-8540, Japan. Electronic address: [email protected].
² Graduate School of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka 815-8540, Japan.
³ Department of Otorhinolaryngology, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
⁴ Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
⁵ Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka 815-8540, Japan.

PMID: 39788848
DOI: 10.1016/j.jvoice.2024.11.041

Abstract

Introduction: Vocal distortion, also known as a scream or growl, is used worldwide as an essential technique in singing, especially in rock and metal, and as an ethnic voice in Mongolian singing. However, the production mechanism of vocal distortion is not yet clearly understood owing to limited research on the behavior of the larynx, which is the source of the distorted voice.

Objectives: This study used high-speed digital imaging (HSDI) to observe the larynx of professional singers with exceptional singing skills and determine the laryngeal dynamics in the voice production of various vocal distortions. In addition, this study aimed to classify vocal distortions based on laryngeal dynamics.

Study design: Cross-sectional study.

Methods: The dynamic behavior of the larynx of six singers (four males and two females) was recorded using HSDI, with the majority of recordings captured at frame rates exceeding 8000 fps. The audio signals were recorded simultaneously. The data were analyzed as topography, glottal area waveforms, long-term average spectra, and spectrograms.

Results: Our analysis revealed that, based on the laryngeal vibration pattern, vocal distortion could be categorized into two primary groups: "periodic" and "aperiodic." In the "periodic" distorted vocalizations, it was suggested that the glottal sound source containing overtone components is generated by vocal fold vibrations, and subharmonic components in the voice are the result of amplitude modulation of the glottal jet by vibrations in the supraglottic region. However, "aperiodic" distorted vocalizations were found to be generated by the vocal folds, which are the main source of noise and generate strong noise due to aperiodic chaotic oscillations of the vocal folds.

Conclusion: The diversity of distorted vocalizations is due to the physiologically and acoustically complex mechanism of voice production in the larynx.

Keywords: Vocal distortion—Growl—Scream—Rock music—Vocal fry—Throat singing.